diff --git a/SabreTools.Library/DatFiles/Json.cs b/SabreTools.Library/DatFiles/Json.cs
index 6cea3d38..e83f3d90 100644
--- a/SabreTools.Library/DatFiles/Json.cs
+++ b/SabreTools.Library/DatFiles/Json.cs
@@ -790,6 +790,10 @@ namespace SabreTools.Library.DatFiles
             string name = null,
                 altName = null,
                 altTitle = null,
+                original = null,
+                msxType = null,
+                remark = null,
+                boot = null,
                 partName = null,
                 partInterface = null,
                 areaName = null,
@@ -814,6 +818,7 @@ namespace SabreTools.Library.DatFiles
                 bios = null;
             ItemStatus? itemStatus = null;
             ItemType? itemType = null;
+            OpenMSXSubType subType = OpenMSXSubType.NULL;
             List<SoftwareListFeature> features = null;
 
             jtr.Read();
@@ -831,8 +836,16 @@ namespace SabreTools.Library.DatFiles
                     datItem.Source = new Source { Index = indexId, Name = filename };
 
                     datItem.Name = name;
+
                     datItem.AltName = altName;
                     datItem.AltTitle = altTitle;
+
+                    datItem.Original = new OpenMSXOriginal(original, null);
+                    datItem.OpenMSXSubType = subType;
+                    datItem.OpenMSXType = msxType;
+                    datItem.Remark = remark;
+                    datItem.Boot = boot;
+
                     datItem.PartName = partName;
                     datItem.PartInterface = partInterface;
                     datItem.Features = features;
@@ -908,6 +921,8 @@ namespace SabreTools.Library.DatFiles
 
                 switch (jtr.Value)
                 {
+                    #region Common
+
                     case "type":
                         itemType = jtr.ReadAsString().AsItemType();
                         break;
@@ -916,6 +931,10 @@ namespace SabreTools.Library.DatFiles
                         name = jtr.ReadAsString();
                         break;
 
+                    #endregion
+
+                    #region AttractMode
+
                     case "alt_romname":
                         altName = jtr.ReadAsString();
                         break;
@@ -924,6 +943,34 @@ namespace SabreTools.Library.DatFiles
                         altTitle = jtr.ReadAsString();
                         break;
 
+                    #endregion
+
+                    #region OpenMSX
+
+                    case "original":
+                        original = jtr.ReadAsString();
+                        break;
+
+                    case "openmsx_subtype":
+                        subType = jtr.ReadAsString().AsOpenMSXSubType();
+                        break;
+
+                    case "openmsx_type":
+                        msxType = jtr.ReadAsString();
+                        break;
+
+                    case "remark":
+                        remark = jtr.ReadAsString();
+                        break;
+
+                    case "boot":
+                        boot = jtr.ReadAsString();
+                        break;
+
+                    #endregion
+
+                    #region SoftwareList
+
                     case "partname":
                         partName = jtr.ReadAsString();
                         break;
@@ -979,6 +1026,8 @@ namespace SabreTools.Library.DatFiles
                         loadFlag = jtr.ReadAsString();
                         break;
 
+                    #endregion
+
                     case "description":
                         biosDescription = jtr.ReadAsString();
                         break;
@@ -2142,6 +2191,8 @@ namespace SabreTools.Library.DatFiles
                         break;
                 }
 
+                #region AttractMode
+
                 if (!string.IsNullOrWhiteSpace(datItem.GetField(Field.AltName, Header.ExcludeFields)))
                 {
                     jtw.WritePropertyName("alt_romname");
@@ -2152,6 +2203,41 @@ namespace SabreTools.Library.DatFiles
                     jtw.WritePropertyName("alt_title");
                     jtw.WriteValue(datItem.AltTitle);
                 }
+
+                #endregion
+
+                #region OpenMSX
+
+                if (!string.IsNullOrWhiteSpace(datItem.GetField(Field.Original, Header.ExcludeFields)))
+                {
+                    jtw.WritePropertyName("original");
+                    jtw.WriteValue(datItem.Original.Original);
+                }
+                if (!string.IsNullOrWhiteSpace(datItem.GetField(Field.OpenMSXSubType, Header.ExcludeFields)))
+                {
+                    jtw.WritePropertyName("openmsx_subtype");
+                    jtw.WriteValue(datItem.OpenMSXSubType);
+                }
+                if (!string.IsNullOrWhiteSpace(datItem.GetField(Field.OpenMSXType, Header.ExcludeFields)))
+                {
+                    jtw.WritePropertyName("openmsx_type");
+                    jtw.WriteValue(datItem.OpenMSXType);
+                }
+                if (!string.IsNullOrWhiteSpace(datItem.GetField(Field.Remark, Header.ExcludeFields)))
+                {
+                    jtw.WritePropertyName("remark");
+                    jtw.WriteValue(datItem.Remark);
+                }
+                if (!string.IsNullOrWhiteSpace(datItem.GetField(Field.Boot, Header.ExcludeFields)))
+                {
+                    jtw.WritePropertyName("boot");
+                    jtw.WriteValue(datItem.Boot);
+                }
+
+                #endregion
+
+                #region SoftwareList
+
                 if (!string.IsNullOrWhiteSpace(datItem.GetField(Field.PartName, Header.ExcludeFields)))
                 {
                     jtw.WritePropertyName("partname");
@@ -2207,6 +2293,8 @@ namespace SabreTools.Library.DatFiles
                     jtw.WriteValue(datItem.LoadFlag);
                 }
 
+                #endregion
+
                 // End item
                 jtw.WriteEndObject();
 
diff --git a/SabreTools.Library/DatFiles/OpenMSX.cs b/SabreTools.Library/DatFiles/OpenMSX.cs
index 2ff84a44..28be49a6 100644
--- a/SabreTools.Library/DatFiles/OpenMSX.cs
+++ b/SabreTools.Library/DatFiles/OpenMSX.cs
@@ -7,6 +7,7 @@ using System.Xml;
 using SabreTools.Library.Data;
 using SabreTools.Library.DatItems;
 using SabreTools.Library.IO;
+using SabreTools.Library.Tools;
 
 namespace SabreTools.Library.DatFiles
 {
@@ -204,7 +205,8 @@ namespace SabreTools.Library.DatFiles
             string filename,
             int indexId)
         {
-            bool containsItems = false;
+            List<DatItem> items = new List<DatItem>();
+            OpenMSXOriginal original = null;
 
             while (!reader.EOF)
             {
@@ -219,30 +221,36 @@ namespace SabreTools.Library.DatFiles
                 switch (reader.Name)
                 {
                     case "rom":
-                        containsItems = ReadRom(reader.ReadSubtree(), machine, diskno, filename, indexId);
+                        DatItem rom = ReadRom(reader.ReadSubtree(), machine, diskno, filename, indexId);
+                        if (rom != null)
+                            items.Add(rom);
 
                         // Skip the rom now that we've processed it
                         reader.Skip();
                         break;
 
                     case "megarom":
-                        containsItems = ReadMegaRom(reader.ReadSubtree(), machine, diskno, filename, indexId);
+                        DatItem megarom = ReadMegaRom(reader.ReadSubtree(), machine, diskno, filename, indexId);
+                        if (megarom != null)
+                            items.Add(megarom);
 
                         // Skip the megarom now that we've processed it
                         reader.Skip();
                         break;
 
                     case "sccpluscart":
-                        containsItems = ReadSccPlusCart(reader.ReadSubtree(), machine, diskno, filename, indexId);
+                        DatItem sccpluscart = ReadSccPlusCart(reader.ReadSubtree(), machine, diskno, filename, indexId);
+                        if (sccpluscart != null)
+                            items.Add(sccpluscart);
 
                         // Skip the sccpluscart now that we've processed it
                         reader.Skip();
                         break;
 
                     case "original":
-                        // bool value = Utilities.GetYesNo(reader.GetAttribute("value");
-                        // string original = reader.ReadElementContentAsString();
-                        reader.Read();
+                        bool? value = reader.GetAttribute("value").AsYesNo();
+                        string orig = reader.ReadElementContentAsString();
+                        original = new OpenMSXOriginal(orig, value);
                         break;
 
                     default:
@@ -251,7 +259,15 @@ namespace SabreTools.Library.DatFiles
                 }
             }
 
-            return containsItems;
+            // If we have any items, loop through and add them
+            foreach (DatItem item in items)
+            {
+                item.CopyMachineInformation(machine);
+                item.Original = original;
+                ParseAddHelper(item);
+            }
+
+            return items.Count > 0;
         }
 
         /// <summary>
@@ -262,7 +278,7 @@ namespace SabreTools.Library.DatFiles
         /// <param name="diskno">Disk number to use when outputting to other DAT formats</param>
         /// <param name="filename">Name of the file to be parsed</param>
         /// <param name="indexId">Index ID for the DAT</param>
-        private bool ReadRom(
+        private DatItem ReadRom(
             XmlReader reader,
             Machine machine,
             int diskno,
@@ -271,8 +287,10 @@ namespace SabreTools.Library.DatFiles
             string filename,
             int indexId)
         {
-            string hash = string.Empty, offset = string.Empty, remark = string.Empty;
-            bool containsItems = false;
+            string hash = string.Empty,
+                offset = string.Empty,
+                type = string.Empty,
+                remark = string.Empty;
 
             while (!reader.EOF)
             {
@@ -287,7 +305,6 @@ namespace SabreTools.Library.DatFiles
                 switch (reader.Name)
                 {
                     case "hash":
-                        containsItems = true;
                         hash = reader.ReadElementContentAsString();
                         break;
 
@@ -296,7 +313,7 @@ namespace SabreTools.Library.DatFiles
                         break;
 
                     case "type":
-                        reader.ReadElementContentAsString();
+                        type = reader.ReadElementContentAsString();
                         break;
 
                     case "remark":
@@ -309,25 +326,30 @@ namespace SabreTools.Library.DatFiles
                 }
             }
 
-            // Create and add the new rom
-            Rom rom = new Rom
+            // If we got a hash, then create and return the item
+            if (!string.IsNullOrWhiteSpace(hash))
             {
-                Name = machine.Name + "_" + diskno + (!string.IsNullOrWhiteSpace(remark) ? " " + remark : string.Empty),
-                Offset = offset,
-                Size = -1,
-                SHA1 = hash,
-
-                Source = new Source
+                return new Rom
                 {
-                    Index = indexId,
-                    Name = filename,
-                },
-            };
+                    Name = machine.Name + "_" + diskno + (!string.IsNullOrWhiteSpace(remark) ? " " + remark : string.Empty),
+                    Offset = offset,
+                    Size = -1,
+                    SHA1 = hash,
 
-            rom.CopyMachineInformation(machine);
-            ParseAddHelper(rom);
+                    Source = new Source
+                    {
+                        Index = indexId,
+                        Name = filename,
+                    },
 
-            return containsItems;
+                    OpenMSXSubType = OpenMSXSubType.Rom,
+                    OpenMSXType = type,
+                    Remark = remark,
+                };
+            }
+
+            // No valid item means returning null
+            return null;
         }
 
         /// <summary>
@@ -338,7 +360,7 @@ namespace SabreTools.Library.DatFiles
         /// <param name="diskno">Disk number to use when outputting to other DAT formats</param>
         /// <param name="filename">Name of the file to be parsed</param>
         /// <param name="indexId">Index ID for the DAT</param>
-        private bool ReadMegaRom(
+        private DatItem ReadMegaRom(
             XmlReader reader,
             Machine machine,
             int diskno,
@@ -347,8 +369,10 @@ namespace SabreTools.Library.DatFiles
             string filename,
             int indexId)
         {
-            string hash = string.Empty, offset = string.Empty, remark = string.Empty;
-            bool containsItems = false;
+            string hash = string.Empty,
+                offset = string.Empty,
+                type = string.Empty,
+                remark = string.Empty;
 
             while (!reader.EOF)
             {
@@ -363,7 +387,6 @@ namespace SabreTools.Library.DatFiles
                 switch (reader.Name)
                 {
                     case "hash":
-                        containsItems = true;
                         hash = reader.ReadElementContentAsString();
                         break;
 
@@ -385,25 +408,30 @@ namespace SabreTools.Library.DatFiles
                 }
             }
 
-            // Create and add the new rom
-            Rom rom = new Rom
+            // If we got a hash, then create and return the item
+            if (!string.IsNullOrWhiteSpace(hash))
             {
-                Name = machine.Name + "_" + diskno + (!string.IsNullOrWhiteSpace(remark) ? " " + remark : string.Empty),
-                Offset = offset,
-                Size = -1,
-                SHA1 = hash,
-
-                Source = new Source
+                return new Rom
                 {
-                    Index = indexId,
-                    Name = filename,
-                },
-            };
+                    Name = machine.Name + "_" + diskno + (!string.IsNullOrWhiteSpace(remark) ? " " + remark : string.Empty),
+                    Offset = offset,
+                    Size = -1,
+                    SHA1 = hash,
 
-            rom.CopyMachineInformation(machine);
-            ParseAddHelper(rom);
+                    Source = new Source
+                    {
+                        Index = indexId,
+                        Name = filename,
+                    },
 
-            return containsItems;
+                    OpenMSXSubType = OpenMSXSubType.MegaRom,
+                    OpenMSXType = type,
+                    Remark = remark,
+                };
+            }
+
+            // No valid item means returning null
+            return null;
         }
 
         /// <summary>
@@ -414,7 +442,7 @@ namespace SabreTools.Library.DatFiles
         /// <param name="diskno">Disk number to use when outputting to other DAT formats</param>
         /// <param name="filename">Name of the file to be parsed</param>
         /// <param name="indexId">Index ID for the DAT</param>
-        private bool ReadSccPlusCart(
+        private DatItem ReadSccPlusCart(
             XmlReader reader,
             Machine machine,
             int diskno,
@@ -423,8 +451,9 @@ namespace SabreTools.Library.DatFiles
             string filename,
             int indexId)
         {
-            string hash = string.Empty, remark = string.Empty;
-            bool containsItems = false;
+            string boot = string.Empty,
+                hash = string.Empty,
+                remark = string.Empty;
 
             while (!reader.EOF)
             {
@@ -439,11 +468,10 @@ namespace SabreTools.Library.DatFiles
                 switch (reader.Name)
                 {
                     case "boot":
-                        reader.ReadElementContentAsString();
+                        boot = reader.ReadElementContentAsString();
                         break;
 
                     case "hash":
-                        containsItems = true;
                         hash = reader.ReadElementContentAsString();
                         break;
 
@@ -457,24 +485,29 @@ namespace SabreTools.Library.DatFiles
                 }
             }
 
-            // Create and add the new rom
-            Rom rom = new Rom
+            // If we got a hash, then create and return the item
+            if (!string.IsNullOrWhiteSpace(hash))
             {
-                Name = machine.Name + "_" + diskno + (!string.IsNullOrWhiteSpace(remark) ? " " + remark : string.Empty),
-                Size = -1,
-                SHA1 = hash,
-
-                Source = new Source
+                return new Rom
                 {
-                    Index = indexId,
-                    Name = filename,
-                },
-            };
+                    Name = machine.Name + "_" + diskno + (!string.IsNullOrWhiteSpace(remark) ? " " + remark : string.Empty),
+                    Size = -1,
+                    SHA1 = hash,
 
-            rom.CopyMachineInformation(machine);
-            ParseAddHelper(rom);
+                    Source = new Source
+                    {
+                        Index = indexId,
+                        Name = filename,
+                    },
 
-            return containsItems;
+                    OpenMSXSubType = OpenMSXSubType.SCCPlusCart,
+                    Boot = boot,
+                    Remark = remark,
+                };
+            }
+
+            // No valid item means returning null
+            return null;
         }
 
         /// <summary>
@@ -689,24 +722,56 @@ namespace SabreTools.Library.DatFiles
                 // Build the state based on excluded fields
                 switch (datItem.ItemType)
                 {
-                    case ItemType.Rom: // Currently this encapsulates rom, megarom, and sccpluscart
+                    case ItemType.Rom:
                         var rom = datItem as Rom;
                         xtw.WriteStartElement("dump");
 
-                        //xtw.WriteStartElement("original");
-                        //xtw.WriteAttributeString("value", "true");
-                        //xtw.WriteString("GoodMSX");
-                        //xtw.WriteEndElement();
+                        if (!Header.ExcludeFields.Contains(Field.Original) && rom.Original != null)
+                        {
+                            xtw.WriteStartElement("original");
+                            xtw.WriteAttributeString("value", rom.Original.Value == true ? "true" : "false");
+                            xtw.WriteString(rom.Original.Original);
+                            xtw.WriteEndElement();
+                        }
 
-                        xtw.WriteStartElement("rom");
-                        if (!string.IsNullOrWhiteSpace(datItem.GetField(Field.Offset, Header.ExcludeFields)))
-                            xtw.WriteElementString("start", rom.Offset);
-                        //xtw.WriteElementString("type", "Normal");
-                        xtw.WriteElementString("hash", rom.GetField(Field.SHA1, Header.ExcludeFields).ToLowerInvariant());
-                        //xtw.WriteElementString("remark", "");
+                        switch (datItem.OpenMSXSubType)
+                        {
+                            // Default to Rom for converting from other formats
+                            case OpenMSXSubType.Rom:
+                            case OpenMSXSubType.NULL:
+                                xtw.WriteStartElement("rom");
+                                xtw.WriteElementString("hash", rom.GetField(Field.SHA1, Header.ExcludeFields).ToLowerInvariant());
+                                if (!string.IsNullOrWhiteSpace(datItem.GetField(Field.Offset, Header.ExcludeFields)))
+                                    xtw.WriteElementString("start", rom.Offset);
+                                if (!string.IsNullOrWhiteSpace(datItem.GetField(Field.OpenMSXType, Header.ExcludeFields)))
+                                    xtw.WriteElementString("type", rom.OpenMSXType);
+                                if (!string.IsNullOrWhiteSpace(datItem.GetField(Field.Remark, Header.ExcludeFields)))
+                                    xtw.WriteElementString("remark", rom.Remark);
+                                xtw.WriteEndElement();
+                                break;
 
-                        // End rom
-                        xtw.WriteEndElement();
+                            case OpenMSXSubType.MegaRom:
+                                xtw.WriteStartElement("megarom");
+                                xtw.WriteElementString("hash", rom.GetField(Field.SHA1, Header.ExcludeFields).ToLowerInvariant());
+                                if (!string.IsNullOrWhiteSpace(datItem.GetField(Field.Offset, Header.ExcludeFields)))
+                                    xtw.WriteElementString("start", rom.Offset);
+                                if (!string.IsNullOrWhiteSpace(datItem.GetField(Field.OpenMSXType, Header.ExcludeFields)))
+                                    xtw.WriteElementString("type", rom.OpenMSXType);
+                                if (!string.IsNullOrWhiteSpace(datItem.GetField(Field.Remark, Header.ExcludeFields)))
+                                    xtw.WriteElementString("remark", rom.Remark);
+                                xtw.WriteEndElement();
+                                break;
+
+                            case OpenMSXSubType.SCCPlusCart:
+                                xtw.WriteStartElement("sccpluscart");
+                                if (!string.IsNullOrWhiteSpace(datItem.GetField(Field.Boot, Header.ExcludeFields)))
+                                    xtw.WriteElementString("boot", rom.Boot);
+                                xtw.WriteElementString("hash", rom.GetField(Field.SHA1, Header.ExcludeFields).ToLowerInvariant());
+                                if (!string.IsNullOrWhiteSpace(datItem.GetField(Field.Remark, Header.ExcludeFields)))
+                                    xtw.WriteElementString("remark", rom.Remark);
+                                xtw.WriteEndElement();
+                                break;
+                        }
 
                         // End dump
                         xtw.WriteEndElement();
diff --git a/SabreTools.Library/DatFiles/SeparatedValue.cs b/SabreTools.Library/DatFiles/SeparatedValue.cs
index 8dab7466..7d1a6714 100644
--- a/SabreTools.Library/DatFiles/SeparatedValue.cs
+++ b/SabreTools.Library/DatFiles/SeparatedValue.cs
@@ -84,6 +84,10 @@ namespace SabreTools.Library.DatFiles
                 string name = null,
                     altName = null,
                     altTitle = null,
+                    original = null,
+                    msxType = null,
+                    remark = null,
+                    boot = null,
                     partName = null,
                     partInterface = null,
                     areaName = null,
@@ -112,6 +116,7 @@ namespace SabreTools.Library.DatFiles
                 long size = -1;
                 ItemType itemType = ItemType.Rom;
                 ItemStatus status = ItemStatus.None;
+                OpenMSXSubType subType = OpenMSXSubType.NULL;
                 List<SoftwareListFeature> features = null;
 
                 // Now we loop through and get values for everything
@@ -527,6 +532,30 @@ namespace SabreTools.Library.DatFiles
 
                         #endregion
 
+                        #region OpenMSX
+
+                        case "DatItem.Original":
+                            original = value;
+                            break;
+
+                        case "DatItem.OpenMSXSubType":
+                            subType = value.AsOpenMSXSubType();
+                            break;
+
+                        case "DatItem.OpenMSXType":
+                            msxType = value;
+                            break;
+
+                        case "DatItem.Remark":
+                            remark = value;
+                            break;
+
+                        case "DatItem.Boot":
+                            boot = value;
+                            break;
+
+                        #endregion
+
                         #region SoftwareList
 
                         case "DatItem.PartName":
@@ -686,6 +715,12 @@ namespace SabreTools.Library.DatFiles
                             AltName = altName,
                             AltTitle = altTitle,
 
+                            Original = new OpenMSXOriginal(original, null),
+                            OpenMSXSubType = subType,
+                            OpenMSXType = msxType,
+                            Remark = remark,
+                            Boot = boot,
+
                             PartName = partName,
                             PartInterface = partInterface,
                             Features = features,
@@ -715,6 +750,12 @@ namespace SabreTools.Library.DatFiles
                             AltName = altName,
                             AltTitle = altTitle,
 
+                            Original = new OpenMSXOriginal(original, null),
+                            OpenMSXSubType = subType,
+                            OpenMSXType = msxType,
+                            Remark = remark,
+                            Boot = boot,
+
                             PartName = partName,
                             PartInterface = partInterface,
                             Features = features,
@@ -747,6 +788,12 @@ namespace SabreTools.Library.DatFiles
                             AltName = altName,
                             AltTitle = altTitle,
 
+                            Original = new OpenMSXOriginal(original, null),
+                            OpenMSXSubType = subType,
+                            OpenMSXType = msxType,
+                            Remark = remark,
+                            Boot = boot,
+
                             PartName = partName,
                             PartInterface = partInterface,
                             Features = features,
@@ -791,6 +838,12 @@ namespace SabreTools.Library.DatFiles
                             AltName = altName,
                             AltTitle = altTitle,
 
+                            Original = new OpenMSXOriginal(original, null),
+                            OpenMSXSubType = subType,
+                            OpenMSXType = msxType,
+                            Remark = remark,
+                            Boot = boot,
+
                             PartName = partName,
                             PartInterface = partInterface,
                             Features = features,
@@ -825,6 +878,12 @@ namespace SabreTools.Library.DatFiles
                             AltName = altName,
                             AltTitle = altTitle,
 
+                            Original = new OpenMSXOriginal(original, null),
+                            OpenMSXSubType = subType,
+                            OpenMSXType = msxType,
+                            Remark = remark,
+                            Boot = boot,
+
                             PartName = partName,
                             PartInterface = partInterface,
                             Features = features,
@@ -873,6 +932,12 @@ namespace SabreTools.Library.DatFiles
                             AltName = altName,
                             AltTitle = altTitle,
 
+                            Original = new OpenMSXOriginal(original, null),
+                            OpenMSXSubType = subType,
+                            OpenMSXType = msxType,
+                            Remark = remark,
+                            Boot = boot,
+
                             PartName = partName,
                             PartInterface = partInterface,
                             Features = features,
@@ -1343,6 +1408,24 @@ namespace SabreTools.Library.DatFiles
 
                 #endregion
 
+                #region OpenMSX
+
+                case "original":
+                    return "DatItem.Original";
+                case "subtype":
+                case "sub type":
+                case "sub-type":
+                case "openmsx_subtype":
+                    return "DatItem.OpenMSXSubType";
+                case "openmsx_type":
+                    return "DatItem.OpenMSXType";
+                case "remark":
+                    return "DatItem.Remark";
+                case "boot":
+                    return "DatItem.Boot";
+
+                #endregion
+
                 #region SoftwareList
 
                 case "partname":
diff --git a/SabreTools.Library/DatItems/Archive.cs b/SabreTools.Library/DatItems/Archive.cs
index d9b5c74c..f0b2348d 100644
--- a/SabreTools.Library/DatItems/Archive.cs
+++ b/SabreTools.Library/DatItems/Archive.cs
@@ -31,6 +31,12 @@
                 AltName = this.AltName,
                 AltTitle = this.AltTitle,
 
+                Original = this.Original,
+                OpenMSXSubType = this.OpenMSXSubType,
+                OpenMSXType = this.OpenMSXType,
+                Remark = this.Remark,
+                Boot = this.Boot,
+
                 PartName = this.PartName,
                 PartInterface = this.PartInterface,
                 Features = this.Features,
diff --git a/SabreTools.Library/DatItems/Auxiliary.cs b/SabreTools.Library/DatItems/Auxiliary.cs
index 0c35f599..f23fde20 100644
--- a/SabreTools.Library/DatItems/Auxiliary.cs
+++ b/SabreTools.Library/DatItems/Auxiliary.cs
@@ -26,6 +26,25 @@ namespace SabreTools.Library.DatItems
 
     #endregion
 
+    #region OpenMSX
+
+    /// <summary>
+    /// Represents the OpenMSX original value
+    /// </summary>
+    public class OpenMSXOriginal
+    {
+        public string Original { get; set; }
+        public bool? Value { get; set; }
+
+        public OpenMSXOriginal(string original, bool? value)
+        {
+            Original = original;
+            Value = value;
+        }
+    }
+
+    #endregion
+
     #region SoftwareList
 
     /// <summary>
diff --git a/SabreTools.Library/DatItems/BiosSet.cs b/SabreTools.Library/DatItems/BiosSet.cs
index e0bd14c2..dbfcf877 100644
--- a/SabreTools.Library/DatItems/BiosSet.cs
+++ b/SabreTools.Library/DatItems/BiosSet.cs
@@ -107,6 +107,12 @@ namespace SabreTools.Library.DatItems
                 AltName = this.AltName,
                 AltTitle = this.AltTitle,
 
+                Original = this.Original,
+                OpenMSXSubType = this.OpenMSXSubType,
+                OpenMSXType = this.OpenMSXType,
+                Remark = this.Remark,
+                Boot = this.Boot,
+
                 PartName = this.PartName,
                 PartInterface = this.PartInterface,
                 Features = this.Features,
@@ -159,7 +165,9 @@ namespace SabreTools.Library.DatItems
                 return false;
 
             // Filter on description
-            if (filter.Description.MatchesNeutral(null, Description) == false)
+            if (filter.Description.MatchesPositiveSet(Description) == false)
+                return false;
+            if (filter.Description.MatchesNegativeSet(Description) == true)
                 return false;
 
             // Filter on default
diff --git a/SabreTools.Library/DatItems/Blank.cs b/SabreTools.Library/DatItems/Blank.cs
index 9d8aa188..cd594d27 100644
--- a/SabreTools.Library/DatItems/Blank.cs
+++ b/SabreTools.Library/DatItems/Blank.cs
@@ -31,6 +31,12 @@
                 AltName = this.AltName,
                 AltTitle = this.AltTitle,
 
+                Original = this.Original,
+                OpenMSXSubType = this.OpenMSXSubType,
+                OpenMSXType = this.OpenMSXType,
+                Remark = this.Remark,
+                Boot = this.Boot,
+
                 PartName = this.PartName,
                 PartInterface = this.PartInterface,
                 Features = this.Features,
diff --git a/SabreTools.Library/DatItems/DatItem.cs b/SabreTools.Library/DatItems/DatItem.cs
index 61f0beb3..d6fb18cb 100644
--- a/SabreTools.Library/DatItems/DatItem.cs
+++ b/SabreTools.Library/DatItems/DatItem.cs
@@ -69,6 +69,41 @@ namespace SabreTools.Library.DatItems
 
         #endregion
 
+        #region OpenMSX
+
+        /// <summary>
+        /// OpenMSX sub item type
+        /// </summary>
+        [JsonProperty("original")]
+        public OpenMSXOriginal Original { get; set; }
+
+        /// <summary>
+        /// OpenMSX sub item type
+        /// </summary>
+        [JsonProperty("openmsx_subtype")]
+        public OpenMSXSubType OpenMSXSubType { get; set; }
+
+        /// <summary>
+        /// OpenMSX sub item type
+        /// </summary>
+        /// <remarks>Not related to the subtype above</remarks>
+        [JsonProperty("openmsx_type")]
+        public string OpenMSXType { get; set; }
+
+        /// <summary>
+        /// Item remark (like a comment)
+        /// </summary>
+        [JsonProperty("remark")]
+        public string Remark { get; set; }
+
+        /// <summary>
+        /// Boot state
+        /// </summary>
+        [JsonProperty("boot")]
+        public string Boot { get; set; }
+
+        #endregion
+
         #region SoftwareList Fields
 
         /// <summary>
@@ -160,6 +195,13 @@ namespace SabreTools.Library.DatItems
             Field.AltName,
             Field.AltTitle,
 
+            // OpenMSX
+            Field.Original,
+            Field.OpenMSXSubType,
+            Field.OpenMSXType,
+            Field.Remark,
+            Field.Boot,
+
             //SoftwareList
             Field.PartName,
             Field.PartInterface,
@@ -286,15 +328,47 @@ namespace SabreTools.Library.DatItems
 
             switch (field)
             {
+                #region Common
+
                 case Field.Name:
                     fieldValue = Name;
                     break;
+
+                #endregion
+
+                #region AttractMode
+
                 case Field.AltName:
                     fieldValue = AltName;
                     break;
                 case Field.AltTitle:
                     fieldValue = AltTitle;
                     break;
+
+                #endregion
+
+                #region OpenMSX
+
+                case Field.Original:
+                    fieldValue = Original.Original;
+                    break;
+                case Field.OpenMSXSubType:
+                    fieldValue = OpenMSXSubType.ToString();
+                    break;
+                case Field.OpenMSXType:
+                    fieldValue = OpenMSXType;
+                    break;
+                case Field.Remark:
+                    fieldValue = Remark;
+                    break;
+                case Field.Boot:
+                    fieldValue = Boot;
+                    break;
+
+                #endregion
+
+                #region SoftwareList
+
                 case Field.PartName:
                     fieldValue = PartName;
                     break;
@@ -323,6 +397,8 @@ namespace SabreTools.Library.DatItems
                     fieldValue = LoadFlag;
                     break;
 
+                #endregion
+
                 case Field.NULL:
                 default:
                     return string.Empty;
@@ -361,6 +437,25 @@ namespace SabreTools.Library.DatItems
 
             #endregion
 
+            #region OpenMSX
+
+            if (mappings.Keys.Contains(Field.Original))
+                Original = new OpenMSXOriginal(mappings[Field.Original], null);
+
+            if (mappings.Keys.Contains(Field.OpenMSXSubType))
+                OpenMSXSubType = mappings[Field.OpenMSXSubType].AsOpenMSXSubType();
+
+            if (mappings.Keys.Contains(Field.OpenMSXType))
+                OpenMSXType = mappings[Field.OpenMSXType];
+
+            if (mappings.Keys.Contains(Field.Remark))
+                Remark = mappings[Field.Remark];
+
+            if (mappings.Keys.Contains(Field.Boot))
+                Boot = mappings[Field.Boot];
+
+            #endregion
+
             #region SoftwareList
 
             if (mappings.Keys.Contains(Field.PartName))
@@ -625,6 +720,40 @@ namespace SabreTools.Library.DatItems
 
             #endregion
 
+            #region OpenMSX
+
+            // Filter on original
+            if (filter.Original.MatchesPositiveSet(Original.Original) == false)
+                return false;
+            if (filter.Original.MatchesNegativeSet(Original.Original) == true)
+                return false;
+
+            // Filter on OpenMSX subtype
+            if (filter.SubType.MatchesPositiveSet(OpenMSXSubType) == false)
+                return false;
+            if (filter.SubType.MatchesNegativeSet(OpenMSXSubType) == true)
+                return false;
+
+            // Filter on OpenMSX type
+            if (filter.OpenMSXType.MatchesPositiveSet(OpenMSXType) == false)
+                return false;
+            if (filter.OpenMSXType.MatchesNegativeSet(OpenMSXType) == true)
+                return false;
+
+            // Filter on remark
+            if (filter.Remark.MatchesPositiveSet(Remark) == false)
+                return false;
+            if (filter.Remark.MatchesNegativeSet(Remark) == true)
+                return false;
+
+            // Filter on boot
+            if (filter.Boot.MatchesPositiveSet(Boot) == false)
+                return false;
+            if (filter.Boot.MatchesNegativeSet(Boot) == true)
+                return false;
+
+            #endregion
+
             #region SoftwareList
 
             // Filter on part name
@@ -708,6 +837,25 @@ namespace SabreTools.Library.DatItems
 
             #endregion
 
+            #region OpenMSX
+
+            if (fields.Contains(Field.Original))
+                Original = null;
+
+            if (fields.Contains(Field.OpenMSXSubType))
+                OpenMSXSubType = OpenMSXSubType.NULL;
+
+            if (fields.Contains(Field.OpenMSXType))
+                OpenMSXType = null;
+
+            if (fields.Contains(Field.Remark))
+                Remark = null;
+
+            if (fields.Contains(Field.Boot))
+                Boot = null;
+
+            #endregion
+
             #region SoftwareList
 
             if (fields.Contains(Field.PartName))
@@ -837,6 +985,25 @@ namespace SabreTools.Library.DatItems
 
             #endregion
 
+            #region OpenMSX
+
+            if (fields.Contains(Field.Original))
+                Original = item.Original;
+
+            if (fields.Contains(Field.OpenMSXSubType))
+                OpenMSXSubType = item.OpenMSXSubType;
+
+            if (fields.Contains(Field.OpenMSXType))
+                OpenMSXType = item.OpenMSXType;
+
+            if (fields.Contains(Field.Remark))
+                Remark = item.Remark;
+
+            if (fields.Contains(Field.Boot))
+                Boot = item.Boot;
+
+            #endregion
+
             #region SoftwareList
 
             if (fields.Contains(Field.PartName))
diff --git a/SabreTools.Library/DatItems/Disk.cs b/SabreTools.Library/DatItems/Disk.cs
index 595da90a..843135d9 100644
--- a/SabreTools.Library/DatItems/Disk.cs
+++ b/SabreTools.Library/DatItems/Disk.cs
@@ -295,6 +295,12 @@ namespace SabreTools.Library.DatItems
                 AltName = this.AltName,
                 AltTitle = this.AltTitle,
 
+                Original = this.Original,
+                OpenMSXSubType = this.OpenMSXSubType,
+                OpenMSXType = this.OpenMSXType,
+                Remark = this.Remark,
+                Boot = this.Boot,
+
                 PartName = this.PartName,
                 PartInterface = this.PartInterface,
                 Features = this.Features,
@@ -341,6 +347,12 @@ namespace SabreTools.Library.DatItems
                 AltName = this.AltName,
                 AltTitle = this.AltTitle,
 
+                Original = this.Original,
+                OpenMSXSubType = this.OpenMSXSubType,
+                OpenMSXType = this.OpenMSXType,
+                Remark = this.Remark,
+                Boot = this.Boot,
+
                 PartName = this.PartName,
                 PartInterface = this.PartInterface,
                 Features = this.Features,
diff --git a/SabreTools.Library/DatItems/Enums.cs b/SabreTools.Library/DatItems/Enums.cs
index 060a5da4..aae939a8 100644
--- a/SabreTools.Library/DatItems/Enums.cs
+++ b/SabreTools.Library/DatItems/Enums.cs
@@ -121,6 +121,16 @@ namespace SabreTools.Library.DatItems
 
         #endregion
 
+        #region OpenMSX
+
+        Original,
+        OpenMSXSubType,
+        OpenMSXType,
+        Remark,
+        Boot,
+
+        #endregion
+
         #region SoftwareList
 
         PartName,
@@ -202,6 +212,18 @@ namespace SabreTools.Library.DatItems
         Blank = 99, // This is not a real type, only used internally
     }
 
+    /// <summary>
+    /// Determine which OpenMSX subtype an item is
+    /// </summary>
+    [Flags]
+    public enum OpenMSXSubType
+    {
+        NULL = 0,
+        Rom = 1,
+        MegaRom = 2,
+        SCCPlusCart = 3,
+    }
+
     /// <summary>
     /// Determine what type of machine it is
     /// </summary>
diff --git a/SabreTools.Library/DatItems/Release.cs b/SabreTools.Library/DatItems/Release.cs
index 42185b75..6353664a 100644
--- a/SabreTools.Library/DatItems/Release.cs
+++ b/SabreTools.Library/DatItems/Release.cs
@@ -135,6 +135,12 @@ namespace SabreTools.Library.DatItems
                 AltName = this.AltName,
                 AltTitle = this.AltTitle,
 
+                Original = this.Original,
+                OpenMSXSubType = this.OpenMSXSubType,
+                OpenMSXType = this.OpenMSXType,
+                Remark = this.Remark,
+                Boot = this.Boot,
+
                 PartName = this.PartName,
                 PartInterface = this.PartInterface,
                 Features = this.Features,
diff --git a/SabreTools.Library/DatItems/Rom.cs b/SabreTools.Library/DatItems/Rom.cs
index 59883223..f5296ef0 100644
--- a/SabreTools.Library/DatItems/Rom.cs
+++ b/SabreTools.Library/DatItems/Rom.cs
@@ -377,6 +377,12 @@ namespace SabreTools.Library.DatItems
                 AltName = this.AltName,
                 AltTitle = this.AltTitle,
 
+                Original = this.Original,
+                OpenMSXSubType = this.OpenMSXSubType,
+                OpenMSXType = this.OpenMSXType,
+                Remark = this.Remark,
+                Boot = this.Boot,
+
                 PartName = this.PartName,
                 PartInterface = this.PartInterface,
                 Features = this.Features,
diff --git a/SabreTools.Library/DatItems/Sample.cs b/SabreTools.Library/DatItems/Sample.cs
index f617885f..d28cca56 100644
--- a/SabreTools.Library/DatItems/Sample.cs
+++ b/SabreTools.Library/DatItems/Sample.cs
@@ -31,6 +31,12 @@
                 AltName = this.AltName,
                 AltTitle = this.AltTitle,
 
+                Original = this.Original,
+                OpenMSXSubType = this.OpenMSXSubType,
+                OpenMSXType = this.OpenMSXType,
+                Remark = this.Remark,
+                Boot = this.Boot,
+
                 PartName = this.PartName,
                 PartInterface = this.PartInterface,
                 Features = this.Features,
diff --git a/SabreTools.Library/Filtering/Filter.cs b/SabreTools.Library/Filtering/Filter.cs
index 67034fe6..83e98993 100644
--- a/SabreTools.Library/Filtering/Filter.cs
+++ b/SabreTools.Library/Filtering/Filter.cs
@@ -267,6 +267,35 @@ namespace SabreTools.Library.Filtering
 
         #endregion
 
+        #region OpenMSX
+
+        /// <summary>
+        /// Include or exclude original value
+        /// </summary>
+        public FilterItem<string> Original { get; private set; } = new FilterItem<string>();
+
+        /// <summary>
+        /// Include or exclude items of a certain OpenMSX subtype
+        /// </summary>
+        public FilterItem<OpenMSXSubType> SubType { get; private set; } = new FilterItem<OpenMSXSubType>() { Positive = OpenMSXSubType.NULL, Negative = OpenMSXSubType.NULL };
+
+        /// <summary>
+        /// Include or exclude OpenMSX type
+        /// </summary>
+        public FilterItem<string> OpenMSXType { get; private set; } = new FilterItem<string>();
+
+        /// <summary>
+        /// Include or exclude remarks
+        /// </summary>
+        public FilterItem<string> Remark { get; private set; } = new FilterItem<string>();
+
+        /// <summary>
+        /// Include or exclude boots
+        /// </summary>
+        public FilterItem<string> Boot { get; private set; } = new FilterItem<string>();
+
+        #endregion
+
         #region SoftwareList
 
         /// <summary>
@@ -860,6 +889,45 @@ namespace SabreTools.Library.Filtering
 
                 #endregion
 
+                #region OpenMSX
+
+                case Field.Original:
+                    if (negate)
+                        Original.NegativeSet.Add(value);
+                    else
+                        Original.PositiveSet.Add(value);
+                    break;
+
+                case Field.OpenMSXSubType:
+                    if (negate)
+                        SubType.Negative |= value.AsOpenMSXSubType();
+                    else
+                        SubType.Positive |= value.AsOpenMSXSubType();
+                    break;
+
+                case Field.OpenMSXType:
+                    if (negate)
+                        OpenMSXType.NegativeSet.Add(value);
+                    else
+                        OpenMSXType.PositiveSet.Add(value);
+                    break;
+
+                case Field.Remark:
+                    if (negate)
+                        Remark.NegativeSet.Add(value);
+                    else
+                        Remark.PositiveSet.Add(value);
+                    break;
+
+                case Field.Boot:
+                    if (negate)
+                        Boot.NegativeSet.Add(value);
+                    else
+                        Boot.PositiveSet.Add(value);
+                    break;
+
+                #endregion
+
                 #region SoftwareList
 
                 case Field.PartName:
diff --git a/SabreTools.Library/Tools/Converters.cs b/SabreTools.Library/Tools/Converters.cs
index d0e75663..5a5d1b56 100644
--- a/SabreTools.Library/Tools/Converters.cs
+++ b/SabreTools.Library/Tools/Converters.cs
@@ -363,7 +363,6 @@ namespace SabreTools.Library.Tools
                 case "alt romname":
                 case "alt-romname":
                     return Field.AltName;
-
                 case "alttitle":
                 case "alt title":
                 case "alt-title":
@@ -374,6 +373,24 @@ namespace SabreTools.Library.Tools
 
                 #endregion
 
+                #region OpenMSX
+
+                case "original":
+                    return Field.Original;
+                case "subtype":
+                case "sub type":
+                case "sub-type":
+                case "openmsx_subtype":
+                    return Field.OpenMSXSubType;
+                case "openmsx_type":
+                    return Field.OpenMSXType;
+                case "remark":
+                    return Field.Remark;
+                case "boot":
+                    return Field.Boot;
+
+                #endregion
+
                 #region SoftwareList
 
                 case "partname":
@@ -665,6 +682,36 @@ namespace SabreTools.Library.Tools
 #endif
         }
 
+        /// <summary>
+        /// Get OpenMSXSubType value from input string
+        /// </summary>
+        /// <param name="itemType">String to get value from</param>
+        /// <returns>OpenMSXSubType value corresponding to the string</returns>
+        public static OpenMSXSubType AsOpenMSXSubType(this string itemType)
+        {
+#if NET_FRAMEWORK
+            switch (itemType?.ToLowerInvariant())
+            {
+                case "rom":
+                    return OpenMSXSubType.Rom;
+                case "megarom":
+                    return OpenMSXSubType.MegaRom;
+                case "sccpluscart":
+                    return OpenMSXSubType.SCCPlusCart;
+                default:
+                    return OpenMSXSubType.NULL;
+            }
+#else
+            return itemType?.ToLowerInvariant() switch
+            {
+                "rom" => OpenMSXSubType.Rom,
+                "megarom" => OpenMSXSubType.MegaRom,
+                "sccpluscart" => OpenMSXSubType.SCCPlusCart,
+                _ => OpenMSXSubType.NULL,
+            };
+#endif
+        }
+
         /// <summary>
         /// Get PackingFlag value from input string
         /// </summary>