diff --git a/NHSE.Core/Structures/Item/FieldItem/FieldItemDefinition.cs b/NHSE.Core/Structures/Item/FieldItem/FieldItemDefinition.cs
index a5d9888..5b3b6c3 100644
--- a/NHSE.Core/Structures/Item/FieldItem/FieldItemDefinition.cs
+++ b/NHSE.Core/Structures/Item/FieldItem/FieldItemDefinition.cs
@@ -6,44 +6,13 @@
 /// <remarks>
 /// These details are extracted from FgMainParam.bcsv
 /// </remarks>
-public class FieldItemDefinition : INamedValue
+/// <param name="Index">Item ID</param>
+/// <param name="Dig">Item ID that the player receives if the item is dug up. Is <see cref="Item.NONE"/> if it cannot be dug up.</param>
+/// <param name="Pick">Item ID that the player receives if the item is picked up. Is <see cref="Item.NONE"/> if it cannot be picked up.</param>
+/// <param name="Name">Internal Name of the Item</param>
+/// <param name="Kind">Classification of item.</param>
+public sealed record FieldItemDefinition(ushort Index, ushort Dig, ushort Pick, string Name, FieldItemKind Kind) : INamedValue
 {
-    /// <summary>
-    /// Item ID
-    /// </summary>
-    public ushort Index { get; }
-
-    /// <summary>
-    /// Internal Name of the Item
-    /// </summary>
-    public string Name { get; }
-
-    /// <summary>
-    /// Item ID that the player receives if the item is dug up.
-    /// </summary>
-    /// <remarks>Is <see cref="Item.NONE"/> if it cannot be dug up.</remarks>
-    public readonly ushort Dig;
-
-    /// <summary>
-    /// Item ID that the player receives if the item is dug up.
-    /// </summary>
-    /// <remarks>Is <see cref="Item.NONE"/> if it cannot be picked up.</remarks>
-    public readonly ushort Pick;
-
-    /// <summary>
-    /// Classification of item.
-    /// </summary>
-    public readonly FieldItemKind Kind;
-
-    public FieldItemDefinition(ushort id, ushort dig, ushort pick, string name, FieldItemKind kind)
-    {
-        Index = id;
-        Dig = dig;
-        Pick = pick;
-        Name = name;
-        Kind = kind;
-    }
-
     /// <summary>
     /// When the field item is picked up, this is the held item ID.
     /// </summary>
diff --git a/NHSE.Core/Structures/Records/EventFlagHouse.cs b/NHSE.Core/Structures/Records/EventFlagHouse.cs
index 4ff2e5a..d7dadd8 100644
--- a/NHSE.Core/Structures/Records/EventFlagHouse.cs
+++ b/NHSE.Core/Structures/Records/EventFlagHouse.cs
@@ -2,23 +2,8 @@
 
 namespace NHSE.Core;
 
-public class EventFlagHouse : INamedValue
+public sealed record EventFlagHouse(short DefaultValue, short MaxValue, ushort Index, string Name) : INamedValue
 {
-    // these are actually unsigned
-    public readonly short DefaultValue;
-    public readonly short MaxValue;
-
-    public ushort Index { get; }
-    public string Name { get; }
-
-    public EventFlagHouse(short init, short max, ushort index, string name)
-    {
-        Name = name;
-        Index = index;
-        DefaultValue = init;
-        MaxValue = max;
-    }
-
     public static readonly IReadOnlyDictionary<ushort, EventFlagHouse> List = new Dictionary<ushort, EventFlagHouse>
     {
         {0x001, new EventFlagHouse(0, 1    , 0001, "HouseOrder1"                                )}, // テント→6x6増築申込
diff --git a/NHSE.Core/Structures/Records/EventFlagLand.cs b/NHSE.Core/Structures/Records/EventFlagLand.cs
index 9a25bbe..53a687d 100644
--- a/NHSE.Core/Structures/Records/EventFlagLand.cs
+++ b/NHSE.Core/Structures/Records/EventFlagLand.cs
@@ -2,23 +2,8 @@
 
 namespace NHSE.Core;
 
-public class EventFlagLand : INamedValue
+public sealed record EventFlagLand(short DefaultValue, short MaxValue, ushort Index, string Name) : INamedValue
 {
-    // these are actually unsigned
-    public readonly short DefaultValue;
-    public readonly short MaxValue;
-
-    public ushort Index { get; }
-    public string Name { get; }
-
-    public EventFlagLand(short init, short max, ushort index, string name)
-    {
-        Name = name;
-        Index = index;
-        DefaultValue = init;
-        MaxValue = max;
-    }
-
     public static readonly IReadOnlyDictionary<ushort, EventFlagLand> List = new Dictionary<ushort, EventFlagLand>
     {
         {0x000, new EventFlagLand(0 , 1    , 0000, "TodayCreateVillage"                         )}, // 今日村作成されたか
diff --git a/NHSE.Core/Structures/Records/EventFlagPlayer.cs b/NHSE.Core/Structures/Records/EventFlagPlayer.cs
index c9046f8..1ff5fd6 100644
--- a/NHSE.Core/Structures/Records/EventFlagPlayer.cs
+++ b/NHSE.Core/Structures/Records/EventFlagPlayer.cs
@@ -3,23 +3,8 @@
 
 namespace NHSE.Core;
 
-public class EventFlagPlayer : INamedValue
+public sealed record EventFlagPlayer(short DefaultValue, short MaxValue, ushort Index, string Name) : INamedValue
 {
-    // these are actually unsigned
-    public readonly short DefaultValue;
-    public readonly short MaxValue;
-
-    public ushort Index { get; }
-    public string Name { get; }
-
-    public EventFlagPlayer(short init, short max, ushort index, string name)
-    {
-        Name = name;
-        Index = index;
-        DefaultValue = init;
-        MaxValue = max;
-    }
-
     public static readonly IReadOnlyDictionary<ushort, EventFlagPlayer> List = new Dictionary<ushort, EventFlagPlayer>
     {
         {0x002, new EventFlagPlayer(0 , 9   , 0002, "PrologueNpcHintCount"                       )}, // NPCの序盤ヒントをいくつまで聞いたか
diff --git a/NHSE.Core/Structures/Records/EventFlagVillager.cs b/NHSE.Core/Structures/Records/EventFlagVillager.cs
index b1a761c..af91277 100644
--- a/NHSE.Core/Structures/Records/EventFlagVillager.cs
+++ b/NHSE.Core/Structures/Records/EventFlagVillager.cs
@@ -3,22 +3,8 @@
 
 namespace NHSE.Core;
 
-public class EventFlagVillager : INamedValue
+public sealed record EventFlagVillager(short Value1, short Value2, ushort Index, string Name) : INamedValue
 {
-    public readonly short Value1;
-    public readonly short Value2;
-
-    public ushort Index { get; }
-    public string Name { get; }
-
-    public EventFlagVillager(short v1, short v2, ushort index, string name)
-    {
-        Name = name;
-        Index = index;
-        Value1 = v1;
-        Value2 = v2;
-    }
-
     public static readonly IReadOnlyDictionary<ushort, EventFlagVillager> List = new Dictionary<ushort, EventFlagVillager>
     {
         {0x000, new EventFlagVillager(0 , 200 , 0000, "NnpcHouseLoan"                              )}, // ローン返済カウント
diff --git a/NHSE.Core/Structures/Records/EventFlagVillagerMemoryPlayer.cs b/NHSE.Core/Structures/Records/EventFlagVillagerMemoryPlayer.cs
index ccb94ce..b858cfd 100644
--- a/NHSE.Core/Structures/Records/EventFlagVillagerMemoryPlayer.cs
+++ b/NHSE.Core/Structures/Records/EventFlagVillagerMemoryPlayer.cs
@@ -2,22 +2,8 @@
 
 namespace NHSE.Core;
 
-public class EventFlagVillagerMemoryPlayer : INamedValue
+public sealed record EventFlagVillagerMemoryPlayer(byte Initial, byte Maximum, ushort Index, string Name) : INamedValue
 {
-    public readonly byte Initial;
-    public readonly byte Maximum;
-
-    public ushort Index { get; }
-    public string Name { get; }
-
-    public EventFlagVillagerMemoryPlayer(byte init, byte max, ushort index, string name)
-    {
-        Name = name;
-        Index = index;
-        Initial = init;
-        Maximum = max;
-    }
-
     public static readonly IReadOnlyDictionary<ushort, EventFlagVillagerMemoryPlayer> List = new Dictionary<ushort, EventFlagVillagerMemoryPlayer>
     {
         {0x00, new EventFlagVillagerMemoryPlayer(0 , 1  , 000, "TalkFreeMultiDayEventNow"                   )}, // （ボツ）今、期間型イベント用のFreeFを聞いたか？