diff --git a/SabreTools.Library/DatFiles/OpenMSX.cs b/SabreTools.Library/DatFiles/OpenMSX.cs
index 36c8d1d2..a8e6fd81 100644
--- a/SabreTools.Library/DatFiles/OpenMSX.cs
+++ b/SabreTools.Library/DatFiles/OpenMSX.cs
@@ -252,8 +252,14 @@ namespace SabreTools.Library.DatFiles
             // If we have any items, loop through and add them
             foreach (DatItem item in items)
             {
+                switch (item.ItemType)
+                {
+                    case ItemType.Rom:
+                        (item as Rom).Original = original;
+                        break;
+                }
+
                 item.CopyMachineInformation(machine);
-                item.Original = original;
                 ParseAddHelper(item);
             }
 
@@ -705,12 +711,12 @@ namespace SabreTools.Library.DatFiles
                             xtw.WriteEndElement();
                         }
 
-                        switch (datItem.OpenMSXSubType)
+                        switch (rom.OpenMSXSubType)
                         {
                             // Default to Rom for converting from other formats
                             case OpenMSXSubType.Rom:
                             case OpenMSXSubType.NULL:
-                                xtw.WriteStartElement(datItem.OpenMSXSubType.FromOpenMSXSubType());
+                                xtw.WriteStartElement(rom.OpenMSXSubType.FromOpenMSXSubType());
                                 xtw.WriteRequiredElementString("hash", rom.SHA1?.ToLowerInvariant());
                                 xtw.WriteOptionalElementString("start", rom.Offset);
                                 xtw.WriteOptionalElementString("type", rom.OpenMSXType);
@@ -719,7 +725,7 @@ namespace SabreTools.Library.DatFiles
                                 break;
 
                             case OpenMSXSubType.MegaRom:
-                                xtw.WriteStartElement(datItem.OpenMSXSubType.FromOpenMSXSubType());
+                                xtw.WriteStartElement(rom.OpenMSXSubType.FromOpenMSXSubType());
                                 xtw.WriteRequiredElementString("hash", rom.SHA1?.ToLowerInvariant());
                                 xtw.WriteOptionalElementString("start", rom.Offset);
                                 xtw.WriteOptionalElementString("type", rom.OpenMSXType);
@@ -728,7 +734,7 @@ namespace SabreTools.Library.DatFiles
                                 break;
 
                             case OpenMSXSubType.SCCPlusCart:
-                                xtw.WriteStartElement(datItem.OpenMSXSubType.FromOpenMSXSubType());
+                                xtw.WriteStartElement(rom.OpenMSXSubType.FromOpenMSXSubType());
                                 xtw.WriteOptionalElementString("boot", rom.Boot);
                                 xtw.WriteRequiredElementString("hash", rom.SHA1?.ToLowerInvariant());
                                 xtw.WriteOptionalElementString("remark", rom.Remark);
diff --git a/SabreTools.Library/DatItems/Adjuster.cs b/SabreTools.Library/DatItems/Adjuster.cs
index dfcc646d..a6b3726d 100644
--- a/SabreTools.Library/DatItems/Adjuster.cs
+++ b/SabreTools.Library/DatItems/Adjuster.cs
@@ -101,12 +101,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/Analog.cs b/SabreTools.Library/DatItems/Analog.cs
index cf9d4c9a..079ed2d0 100644
--- a/SabreTools.Library/DatItems/Analog.cs
+++ b/SabreTools.Library/DatItems/Analog.cs
@@ -64,12 +64,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/Archive.cs b/SabreTools.Library/DatItems/Archive.cs
index 4034f222..7bc0a472 100644
--- a/SabreTools.Library/DatItems/Archive.cs
+++ b/SabreTools.Library/DatItems/Archive.cs
@@ -77,12 +77,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/BiosSet.cs b/SabreTools.Library/DatItems/BiosSet.cs
index 8e379862..491f62fc 100644
--- a/SabreTools.Library/DatItems/BiosSet.cs
+++ b/SabreTools.Library/DatItems/BiosSet.cs
@@ -95,12 +95,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/Blank.cs b/SabreTools.Library/DatItems/Blank.cs
index 674651ec..996ae0d7 100644
--- a/SabreTools.Library/DatItems/Blank.cs
+++ b/SabreTools.Library/DatItems/Blank.cs
@@ -32,12 +32,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/Chip.cs b/SabreTools.Library/DatItems/Chip.cs
index 805f5cfd..68d2077d 100644
--- a/SabreTools.Library/DatItems/Chip.cs
+++ b/SabreTools.Library/DatItems/Chip.cs
@@ -106,12 +106,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/Condition.cs b/SabreTools.Library/DatItems/Condition.cs
index 46949d4a..8f1c4467 100644
--- a/SabreTools.Library/DatItems/Condition.cs
+++ b/SabreTools.Library/DatItems/Condition.cs
@@ -99,12 +99,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/Configuration.cs b/SabreTools.Library/DatItems/Configuration.cs
index c3de4942..b4e4b22d 100644
--- a/SabreTools.Library/DatItems/Configuration.cs
+++ b/SabreTools.Library/DatItems/Configuration.cs
@@ -140,12 +140,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/Control.cs b/SabreTools.Library/DatItems/Control.cs
index 55cec761..5172f716 100644
--- a/SabreTools.Library/DatItems/Control.cs
+++ b/SabreTools.Library/DatItems/Control.cs
@@ -164,12 +164,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/DatItem.cs b/SabreTools.Library/DatItems/DatItem.cs
index ba5ed6e4..8c806560 100644
--- a/SabreTools.Library/DatItems/DatItem.cs
+++ b/SabreTools.Library/DatItems/DatItem.cs
@@ -66,42 +66,6 @@ namespace SabreTools.Library.DatItems
 
         #endregion
 
-        #region OpenMSX
-
-        /// <summary>
-        /// OpenMSX sub item type
-        /// </summary>
-        [JsonProperty("original", DefaultValueHandling = DefaultValueHandling.Ignore)]
-        public Original Original { get; set; }
-
-        /// <summary>
-        /// OpenMSX sub item type
-        /// </summary>
-        [JsonProperty("openmsx_subtype", DefaultValueHandling = DefaultValueHandling.Ignore)]
-        [JsonConverter(typeof(StringEnumConverter))]
-        public OpenMSXSubType OpenMSXSubType { get; set; }
-
-        /// <summary>
-        /// OpenMSX sub item type
-        /// </summary>
-        /// <remarks>Not related to the subtype above</remarks>
-        [JsonProperty("openmsx_type", DefaultValueHandling = DefaultValueHandling.Ignore)]
-        public string OpenMSXType { get; set; }
-
-        /// <summary>
-        /// Item remark (like a comment)
-        /// </summary>
-        [JsonProperty("remark", DefaultValueHandling = DefaultValueHandling.Ignore)]
-        public string Remark { get; set; }
-
-        /// <summary>
-        /// Boot state
-        /// </summary>
-        [JsonProperty("boot", DefaultValueHandling = DefaultValueHandling.Ignore)]
-        public string Boot { get; set; }
-
-        #endregion
-
         #region Metadata information
 
         /// <summary>
@@ -337,25 +301,6 @@ namespace SabreTools.Library.DatItems
                 AltTitle = mappings[Field.DatItem_AltTitle];
 
             #endregion
-
-            #region OpenMSX
-
-            if (mappings.Keys.Contains(Field.DatItem_Original))
-                Original = new Original() { Content = mappings[Field.DatItem_Original] };
-
-            if (mappings.Keys.Contains(Field.DatItem_OpenMSXSubType))
-                OpenMSXSubType = mappings[Field.DatItem_OpenMSXSubType].AsOpenMSXSubType();
-
-            if (mappings.Keys.Contains(Field.DatItem_OpenMSXType))
-                OpenMSXType = mappings[Field.DatItem_OpenMSXType];
-
-            if (mappings.Keys.Contains(Field.DatItem_Remark))
-                Remark = mappings[Field.DatItem_Remark];
-
-            if (mappings.Keys.Contains(Field.DatItem_Boot))
-                Boot = mappings[Field.DatItem_Boot];
-
-            #endregion
         }
 
         #endregion
@@ -700,40 +645,6 @@ namespace SabreTools.Library.DatItems
 
             #endregion
 
-            #region OpenMSX
-
-            // Filter on original
-            if (filter.DatItem_Original.MatchesPositiveSet(Original?.Content) == false)
-                return false;
-            if (filter.DatItem_Original.MatchesNegativeSet(Original?.Content) == true)
-                return false;
-
-            // Filter on OpenMSX subtype
-            if (filter.DatItem_OpenMSXSubType.MatchesPositiveSet(OpenMSXSubType) == false)
-                return false;
-            if (filter.DatItem_OpenMSXSubType.MatchesNegativeSet(OpenMSXSubType) == true)
-                return false;
-
-            // Filter on OpenMSX type
-            if (filter.DatItem_OpenMSXType.MatchesPositiveSet(OpenMSXType) == false)
-                return false;
-            if (filter.DatItem_OpenMSXType.MatchesNegativeSet(OpenMSXType) == true)
-                return false;
-
-            // Filter on remark
-            if (filter.DatItem_Remark.MatchesPositiveSet(Remark) == false)
-                return false;
-            if (filter.DatItem_Remark.MatchesNegativeSet(Remark) == true)
-                return false;
-
-            // Filter on boot
-            if (filter.DatItem_Boot.MatchesPositiveSet(Boot) == false)
-                return false;
-            if (filter.DatItem_Boot.MatchesNegativeSet(Boot) == true)
-                return false;
-
-            #endregion
-
             return true;
         }
 
@@ -755,25 +666,6 @@ namespace SabreTools.Library.DatItems
                 AltTitle = null;
 
             #endregion
-
-            #region OpenMSX
-
-            if (fields.Contains(Field.DatItem_Original))
-                Original = null;
-
-            if (fields.Contains(Field.DatItem_OpenMSXSubType))
-                OpenMSXSubType = OpenMSXSubType.NULL;
-
-            if (fields.Contains(Field.DatItem_OpenMSXType))
-                OpenMSXType = null;
-
-            if (fields.Contains(Field.DatItem_Remark))
-                Remark = null;
-
-            if (fields.Contains(Field.DatItem_Boot))
-                Boot = null;
-
-            #endregion
         }
 
         /// <summary>
@@ -872,25 +764,6 @@ namespace SabreTools.Library.DatItems
                 AltTitle = item.AltTitle;
 
             #endregion
-
-            #region OpenMSX
-
-            if (fields.Contains(Field.DatItem_Original))
-                Original = item.Original;
-
-            if (fields.Contains(Field.DatItem_OpenMSXSubType))
-                OpenMSXSubType = item.OpenMSXSubType;
-
-            if (fields.Contains(Field.DatItem_OpenMSXType))
-                OpenMSXType = item.OpenMSXType;
-
-            if (fields.Contains(Field.DatItem_Remark))
-                Remark = item.Remark;
-
-            if (fields.Contains(Field.DatItem_Boot))
-                Boot = item.Boot;
-
-            #endregion
         }
 
         #endregion
diff --git a/SabreTools.Library/DatItems/Device.cs b/SabreTools.Library/DatItems/Device.cs
index 54879ceb..c9672929 100644
--- a/SabreTools.Library/DatItems/Device.cs
+++ b/SabreTools.Library/DatItems/Device.cs
@@ -115,12 +115,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/DeviceReference.cs b/SabreTools.Library/DatItems/DeviceReference.cs
index 2fc1ac0a..693e4ecf 100644
--- a/SabreTools.Library/DatItems/DeviceReference.cs
+++ b/SabreTools.Library/DatItems/DeviceReference.cs
@@ -77,12 +77,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/DipSwitch.cs b/SabreTools.Library/DatItems/DipSwitch.cs
index fe7026d3..56397875 100644
--- a/SabreTools.Library/DatItems/DipSwitch.cs
+++ b/SabreTools.Library/DatItems/DipSwitch.cs
@@ -158,12 +158,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/Disk.cs b/SabreTools.Library/DatItems/Disk.cs
index 7d7b5f20..c04f3beb 100644
--- a/SabreTools.Library/DatItems/Disk.cs
+++ b/SabreTools.Library/DatItems/Disk.cs
@@ -230,12 +230,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
@@ -269,12 +263,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/Display.cs b/SabreTools.Library/DatItems/Display.cs
index c2e8704d..cd361eb3 100644
--- a/SabreTools.Library/DatItems/Display.cs
+++ b/SabreTools.Library/DatItems/Display.cs
@@ -181,12 +181,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/Driver.cs b/SabreTools.Library/DatItems/Driver.cs
index 54a7ef22..ec6baa9c 100644
--- a/SabreTools.Library/DatItems/Driver.cs
+++ b/SabreTools.Library/DatItems/Driver.cs
@@ -97,12 +97,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/Enums.cs b/SabreTools.Library/DatItems/Enums.cs
index 8d2b0ad1..e34ccaca 100644
--- a/SabreTools.Library/DatItems/Enums.cs
+++ b/SabreTools.Library/DatItems/Enums.cs
@@ -78,7 +78,7 @@ namespace SabreTools.Library.DatItems
     /// List of valid field types within a DatItem/Machine
     /// </summary>
     /// TODO: Move this to a more common location
-    /// TODO: Should this be split into separate enums?
+    /// TODO: Ensure the order of these after all shuffling
     public enum Field : int
     {
         NULL = 0,
@@ -241,16 +241,6 @@ namespace SabreTools.Library.DatItems
 
         #endregion
 
-        #region OpenMSX
-
-        DatItem_Original,
-        DatItem_OpenMSXSubType,
-        DatItem_OpenMSXType,
-        DatItem_Remark,
-        DatItem_Boot,
-
-        #endregion
-
         #region SoftwareList
 
         // Part
@@ -291,6 +281,13 @@ namespace SabreTools.Library.DatItems
         DatItem_Optional,
         DatItem_Inverted,
 
+        // Rom (OpenMSX)
+        DatItem_Original,
+        DatItem_OpenMSXSubType,
+        DatItem_OpenMSXType,
+        DatItem_Remark,
+        DatItem_Boot,
+
         // Rom (SoftwareList)
         DatItem_AreaName,
         DatItem_AreaSize,
diff --git a/SabreTools.Library/DatItems/Extension.cs b/SabreTools.Library/DatItems/Extension.cs
index 6de8405f..3a0a71ed 100644
--- a/SabreTools.Library/DatItems/Extension.cs
+++ b/SabreTools.Library/DatItems/Extension.cs
@@ -77,12 +77,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/Feature.cs b/SabreTools.Library/DatItems/Feature.cs
index a61942a4..395c8f57 100644
--- a/SabreTools.Library/DatItems/Feature.cs
+++ b/SabreTools.Library/DatItems/Feature.cs
@@ -87,12 +87,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/Info.cs b/SabreTools.Library/DatItems/Info.cs
index 3f90f391..14f9da20 100644
--- a/SabreTools.Library/DatItems/Info.cs
+++ b/SabreTools.Library/DatItems/Info.cs
@@ -85,12 +85,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/Input.cs b/SabreTools.Library/DatItems/Input.cs
index e56cfd8f..93d671a9 100644
--- a/SabreTools.Library/DatItems/Input.cs
+++ b/SabreTools.Library/DatItems/Input.cs
@@ -99,12 +99,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/Instance.cs b/SabreTools.Library/DatItems/Instance.cs
index 9e9b6abe..457ea338 100644
--- a/SabreTools.Library/DatItems/Instance.cs
+++ b/SabreTools.Library/DatItems/Instance.cs
@@ -86,12 +86,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/Location.cs b/SabreTools.Library/DatItems/Location.cs
index 7fed8d7e..3b9bd688 100644
--- a/SabreTools.Library/DatItems/Location.cs
+++ b/SabreTools.Library/DatItems/Location.cs
@@ -94,12 +94,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/Media.cs b/SabreTools.Library/DatItems/Media.cs
index 38982384..d14f9adf 100644
--- a/SabreTools.Library/DatItems/Media.cs
+++ b/SabreTools.Library/DatItems/Media.cs
@@ -142,12 +142,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
@@ -173,12 +167,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/Port.cs b/SabreTools.Library/DatItems/Port.cs
index 311d193a..033a48e4 100644
--- a/SabreTools.Library/DatItems/Port.cs
+++ b/SabreTools.Library/DatItems/Port.cs
@@ -74,12 +74,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/RamOption.cs b/SabreTools.Library/DatItems/RamOption.cs
index bcda5985..672557a6 100644
--- a/SabreTools.Library/DatItems/RamOption.cs
+++ b/SabreTools.Library/DatItems/RamOption.cs
@@ -95,12 +95,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/Release.cs b/SabreTools.Library/DatItems/Release.cs
index 5eb4960c..16a7520c 100644
--- a/SabreTools.Library/DatItems/Release.cs
+++ b/SabreTools.Library/DatItems/Release.cs
@@ -117,12 +117,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/Rom.cs b/SabreTools.Library/DatItems/Rom.cs
index 6c7c634d..a8697cda 100644
--- a/SabreTools.Library/DatItems/Rom.cs
+++ b/SabreTools.Library/DatItems/Rom.cs
@@ -171,6 +171,42 @@ namespace SabreTools.Library.DatItems
 
         #endregion
 
+        #region OpenMSX
+
+        /// <summary>
+        /// OpenMSX sub item type
+        /// </summary>
+        [JsonProperty("original", DefaultValueHandling = DefaultValueHandling.Ignore)]
+        public Original Original { get; set; }
+
+        /// <summary>
+        /// OpenMSX sub item type
+        /// </summary>
+        [JsonProperty("openmsx_subtype", DefaultValueHandling = DefaultValueHandling.Ignore)]
+        [JsonConverter(typeof(StringEnumConverter))]
+        public OpenMSXSubType OpenMSXSubType { get; set; }
+
+        /// <summary>
+        /// OpenMSX sub item type
+        /// </summary>
+        /// <remarks>Not related to the subtype above</remarks>
+        [JsonProperty("openmsx_type", DefaultValueHandling = DefaultValueHandling.Ignore)]
+        public string OpenMSXType { get; set; }
+
+        /// <summary>
+        /// Item remark (like a comment)
+        /// </summary>
+        [JsonProperty("remark", DefaultValueHandling = DefaultValueHandling.Ignore)]
+        public string Remark { get; set; }
+
+        /// <summary>
+        /// Boot state
+        /// </summary>
+        [JsonProperty("boot", DefaultValueHandling = DefaultValueHandling.Ignore)]
+        public string Boot { get; set; }
+
+        #endregion
+
         #region SoftwareList
 
         /// <summary>
@@ -284,6 +320,25 @@ namespace SabreTools.Library.DatItems
 
             #endregion
 
+            #region OpenMSX
+
+            if (mappings.Keys.Contains(Field.DatItem_Original))
+                Original = new Original() { Content = mappings[Field.DatItem_Original] };
+
+            if (mappings.Keys.Contains(Field.DatItem_OpenMSXSubType))
+                OpenMSXSubType = mappings[Field.DatItem_OpenMSXSubType].AsOpenMSXSubType();
+
+            if (mappings.Keys.Contains(Field.DatItem_OpenMSXType))
+                OpenMSXType = mappings[Field.DatItem_OpenMSXType];
+
+            if (mappings.Keys.Contains(Field.DatItem_Remark))
+                Remark = mappings[Field.DatItem_Remark];
+
+            if (mappings.Keys.Contains(Field.DatItem_Boot))
+                Boot = mappings[Field.DatItem_Boot];
+
+            #endregion
+
             #region SoftwareList
 
             if (mappings.Keys.Contains(Field.DatItem_AreaName))
@@ -760,6 +815,40 @@ namespace SabreTools.Library.DatItems
 
             #endregion
 
+            #region OpenMSX
+
+            // Filter on original
+            if (filter.DatItem_Original.MatchesPositiveSet(Original?.Content) == false)
+                return false;
+            if (filter.DatItem_Original.MatchesNegativeSet(Original?.Content) == true)
+                return false;
+
+            // Filter on OpenMSX subtype
+            if (filter.DatItem_OpenMSXSubType.MatchesPositiveSet(OpenMSXSubType) == false)
+                return false;
+            if (filter.DatItem_OpenMSXSubType.MatchesNegativeSet(OpenMSXSubType) == true)
+                return false;
+
+            // Filter on OpenMSX type
+            if (filter.DatItem_OpenMSXType.MatchesPositiveSet(OpenMSXType) == false)
+                return false;
+            if (filter.DatItem_OpenMSXType.MatchesNegativeSet(OpenMSXType) == true)
+                return false;
+
+            // Filter on remark
+            if (filter.DatItem_Remark.MatchesPositiveSet(Remark) == false)
+                return false;
+            if (filter.DatItem_Remark.MatchesNegativeSet(Remark) == true)
+                return false;
+
+            // Filter on boot
+            if (filter.DatItem_Boot.MatchesPositiveSet(Boot) == false)
+                return false;
+            if (filter.DatItem_Boot.MatchesNegativeSet(Boot) == true)
+                return false;
+
+            #endregion
+
             #region SoftwareList
 
             // Filter on area name
@@ -887,6 +976,25 @@ namespace SabreTools.Library.DatItems
 
             #endregion
 
+            #region OpenMSX
+
+            if (fields.Contains(Field.DatItem_Original))
+                Original = null;
+
+            if (fields.Contains(Field.DatItem_OpenMSXSubType))
+                OpenMSXSubType = OpenMSXSubType.NULL;
+
+            if (fields.Contains(Field.DatItem_OpenMSXType))
+                OpenMSXType = null;
+
+            if (fields.Contains(Field.DatItem_Remark))
+                Remark = null;
+
+            if (fields.Contains(Field.DatItem_Boot))
+                Boot = null;
+
+            #endregion
+
             #region SoftwareList
 
             if (fields.Contains(Field.DatItem_AreaName))
@@ -1101,6 +1209,25 @@ namespace SabreTools.Library.DatItems
 
             #endregion
 
+            #region OpenMSX
+
+            if (fields.Contains(Field.DatItem_Original))
+                Original = newItem.Original;
+
+            if (fields.Contains(Field.DatItem_OpenMSXSubType))
+                OpenMSXSubType = newItem.OpenMSXSubType;
+
+            if (fields.Contains(Field.DatItem_OpenMSXType))
+                OpenMSXType = newItem.OpenMSXType;
+
+            if (fields.Contains(Field.DatItem_Remark))
+                Remark = newItem.Remark;
+
+            if (fields.Contains(Field.DatItem_Boot))
+                Boot = newItem.Boot;
+
+            #endregion
+
             #region SoftwareList
 
             if (fields.Contains(Field.DatItem_AreaName))
diff --git a/SabreTools.Library/DatItems/Sample.cs b/SabreTools.Library/DatItems/Sample.cs
index 7e517efe..88708cec 100644
--- a/SabreTools.Library/DatItems/Sample.cs
+++ b/SabreTools.Library/DatItems/Sample.cs
@@ -77,12 +77,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/Setting.cs b/SabreTools.Library/DatItems/Setting.cs
index 86f80bed..9b2f6233 100644
--- a/SabreTools.Library/DatItems/Setting.cs
+++ b/SabreTools.Library/DatItems/Setting.cs
@@ -109,12 +109,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/SharedFeature.cs b/SabreTools.Library/DatItems/SharedFeature.cs
index 43a7b012..99b7c124 100644
--- a/SabreTools.Library/DatItems/SharedFeature.cs
+++ b/SabreTools.Library/DatItems/SharedFeature.cs
@@ -85,12 +85,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/Slot.cs b/SabreTools.Library/DatItems/Slot.cs
index 69ea501f..26f92e43 100644
--- a/SabreTools.Library/DatItems/Slot.cs
+++ b/SabreTools.Library/DatItems/Slot.cs
@@ -85,12 +85,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/SlotOption.cs b/SabreTools.Library/DatItems/SlotOption.cs
index d8ddff96..2f47fc3b 100644
--- a/SabreTools.Library/DatItems/SlotOption.cs
+++ b/SabreTools.Library/DatItems/SlotOption.cs
@@ -94,12 +94,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/SoftwareList.cs b/SabreTools.Library/DatItems/SoftwareList.cs
index c2f570c3..70f85d59 100644
--- a/SabreTools.Library/DatItems/SoftwareList.cs
+++ b/SabreTools.Library/DatItems/SoftwareList.cs
@@ -97,12 +97,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,
diff --git a/SabreTools.Library/DatItems/Sound.cs b/SabreTools.Library/DatItems/Sound.cs
index c7ff7160..929248b3 100644
--- a/SabreTools.Library/DatItems/Sound.cs
+++ b/SabreTools.Library/DatItems/Sound.cs
@@ -64,12 +64,6 @@ 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,
-
                 Machine = this.Machine.Clone() as Machine,
                 Source = this.Source.Clone() as Source,
                 Remove = this.Remove,