diff --git a/Assets/VRM10/Editor/ScriptedImporter/VrmScriptedImporterImpl.cs b/Assets/VRM10/Editor/ScriptedImporter/VrmScriptedImporterImpl.cs
index a6a2705f9..305bcccfc 100644
--- a/Assets/VRM10/Editor/ScriptedImporter/VrmScriptedImporterImpl.cs
+++ b/Assets/VRM10/Editor/ScriptedImporter/VrmScriptedImporterImpl.cs
@@ -40,7 +40,7 @@ namespace UniVRM10
 
             var materialGenerator = GetMaterialDescriptorGenerator(renderPipeline);
 
-            using (var loader = new Vrm10Importer(result, extractedObjects, materialGenerator: materialGenerator))
+            using (var loader = new Vrm10Importer(result, controlRigInitialRotations: null, externalObjectMap: extractedObjects, materialGenerator: materialGenerator))
             {
                 // settings TextureImporters
                 foreach (var textureInfo in loader.TextureDescriptorGenerator.Get().GetEnumerable())
diff --git a/Assets/VRM10/Runtime/Components/Vrm10Instance/Vrm10Instance.cs b/Assets/VRM10/Runtime/Components/Vrm10Instance/Vrm10Instance.cs
index b2822cc0e..e3a888704 100644
--- a/Assets/VRM10/Runtime/Components/Vrm10Instance/Vrm10Instance.cs
+++ b/Assets/VRM10/Runtime/Components/Vrm10Instance/Vrm10Instance.cs
@@ -53,8 +53,15 @@ namespace UniVRM10
 
         private UniHumanoid.Humanoid m_humanoid;
         private Vrm10Runtime m_runtime;
-        private ControlRigGenerationOption m_controlRigGenerationOption = ControlRigGenerationOption.None;
-        private Dictionary<HumanBodyBones, Quaternion> m_initialRotations;
+
+        /// <summary>
+        /// ControlRig の生成オプション
+        /// 
+        /// null: ControlRigGenerationOption.None
+        /// empty: ControlRigGenerationOption.Generate = Vrm0XCompatibleRig
+        /// other: ControlRigGenerationOption.Vrm0XCompatibleWithXR_EXT_hand_tracking など
+        /// </summary>
+        private IReadOnlyDictionary<HumanBodyBones, Quaternion> m_controlRigInitialRotations;
 
         /// <summary>
         /// VRM ファイルに記録された Humanoid ボーンに対応します。
@@ -81,16 +88,15 @@ namespace UniVRM10
             {
                 if (m_runtime == null)
                 {
-                    m_runtime = new Vrm10Runtime(this, m_controlRigGenerationOption, m_initialRotations);
+                    m_runtime = new Vrm10Runtime(this, m_controlRigInitialRotations);
                 }
                 return m_runtime;
             }
         }
 
-        internal void InitializeAtRuntime(ControlRigGenerationOption controlRigGenerationOption, Dictionary<HumanBodyBones, Quaternion> initialRotations = null)
+        internal void InitializeAtRuntime(IReadOnlyDictionary<HumanBodyBones, Quaternion> controlRigInitialRotations)
         {
-            m_controlRigGenerationOption = controlRigGenerationOption;
-            m_initialRotations = initialRotations;
+            m_controlRigInitialRotations = controlRigInitialRotations;
         }
 
         void Start()
diff --git a/Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/ControlRigGenerationOption.cs b/Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/ControlRigGenerationOption.cs
deleted file mode 100644
index 6ebb0e6e4..000000000
--- a/Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/ControlRigGenerationOption.cs
+++ /dev/null
@@ -1,16 +0,0 @@
-namespace UniVRM10
-{
-    public enum ControlRigGenerationOption
-    {
-        /// <summary>
-        /// コントロールリグを生成しません。
-        /// </summary>
-        None,
-
-        /// <summary>
-        /// 推奨されるオプションです。
-        /// コントロールリグのボーン Transform を生成し、Root の Animator はコントロールリグのボーンを制御するようになります。
-        /// </summary>
-        Generate,
-    }
-}
\ No newline at end of file
diff --git a/Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/ControlRigGenerationOption.cs.meta b/Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/ControlRigGenerationOption.cs.meta
deleted file mode 100644
index f6e9a90c1..000000000
--- a/Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/ControlRigGenerationOption.cs.meta
+++ /dev/null
@@ -1,3 +0,0 @@
-fileFormatVersion: 2
-guid: 9723f89e671a460188d12cbcceccaa4e
-timeCreated: 1663314138
\ No newline at end of file
diff --git a/Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/Rigs.meta b/Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/Rigs.meta
new file mode 100644
index 000000000..990bb33f5
--- /dev/null
+++ b/Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/Rigs.meta
@@ -0,0 +1,8 @@
+fileFormatVersion: 2
+guid: ebc9416609f7b734f87e487dfa0ae076
+folderAsset: yes
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/Rigs/ControlRigGenerationOption.cs b/Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/Rigs/ControlRigGenerationOption.cs
new file mode 100644
index 000000000..eaae70332
--- /dev/null
+++ b/Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/Rigs/ControlRigGenerationOption.cs
@@ -0,0 +1,50 @@
+using System;
+using System.Collections.Generic;
+using UnityEngine;
+
+namespace UniVRM10
+{
+    public enum ControlRigGenerationOption
+    {
+        /// <summary>
+        /// コントロールリグを生成しません。
+        /// </summary>
+        None = 0,
+
+        /// <summary>
+        /// 推奨されるオプションです。
+        /// コントロールリグのボーン Transform を生成し、Root の Animator はコントロールリグのボーンを制御するようになります。
+        /// </summary>
+        Generate = 1,
+        Vrm0XCompatibleRig = 1,
+
+        /// <summary>
+        /// コントロールリグのボーン Transform を生成し、Root の Animator はコントロールリグのボーンを制御するようになります。
+        /// 手と指に関して、XR_EXT_hand_tracking の初期回転を持ちます。
+        /// https://registry.khronos.org/OpenXR/specs/1.0/html/xrspec.html#XR_EXT_hand_tracking
+        /// </summary>
+        Vrm0XCompatibleWithXR_EXT_hand_tracking = 2,
+    }
+
+    public static class ControlRigGenerationOptionExtensions
+    {
+        public static IReadOnlyDictionary<HumanBodyBones, Quaternion> ToInitialRotations(this ControlRigGenerationOption option)
+        {
+            switch (option)
+            {
+                case ControlRigGenerationOption.None:
+                    return null;
+
+                case ControlRigGenerationOption.Generate:
+                    // case ControlRigGenerationOption.Vrm0XCompatibleRig:
+                    return Vrm0XCompatibleRig.InitialRotations;
+
+                case ControlRigGenerationOption.Vrm0XCompatibleWithXR_EXT_hand_tracking:
+                    return XR_EXT_hand_tracking.InitialRotations;
+
+                default:
+                    throw new ArgumentException();
+            }
+        }
+    }
+}
diff --git a/Assets/VRM10/Runtime/Components/Vrm10Runtime/OpenXRHandTracking.cs.meta b/Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/Rigs/ControlRigGenerationOption.cs.meta
similarity index 83%
rename from Assets/VRM10/Runtime/Components/Vrm10Runtime/OpenXRHandTracking.cs.meta
rename to Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/Rigs/ControlRigGenerationOption.cs.meta
index bb500746b..f32b76551 100644
--- a/Assets/VRM10/Runtime/Components/Vrm10Runtime/OpenXRHandTracking.cs.meta
+++ b/Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/Rigs/ControlRigGenerationOption.cs.meta
@@ -1,5 +1,5 @@
 fileFormatVersion: 2
-guid: 45a6dbb978533164dafbcbf6f28e5117
+guid: 254b61afe523dd74b9579ff1e971bee7
 MonoImporter:
   externalObjects: {}
   serializedVersion: 2
diff --git a/Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/Rigs/Vrm0XCompatibleRig.cs b/Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/Rigs/Vrm0XCompatibleRig.cs
new file mode 100644
index 000000000..ddc033dc5
--- /dev/null
+++ b/Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/Rigs/Vrm0XCompatibleRig.cs
@@ -0,0 +1,15 @@
+using System.Collections.Generic;
+using UnityEngine;
+
+namespace UniVRM10
+{
+    public static class Vrm0XCompatibleRig
+    {
+        /// <summary>
+        /// 空の Dictionary を返します。
+        /// HumanBodyBones に対応する Quaternion が無い場合は Quaternion.Identity を採用する仕様です。
+        /// VRM-0.X では T-Pose のときにすべてのボーンが Quaternion.Identity です。
+        /// </summary>
+        public static IReadOnlyDictionary<HumanBodyBones, Quaternion> InitialRotations => new Dictionary<HumanBodyBones, Quaternion>();
+    }
+}
diff --git a/Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/Rigs/Vrm0XCompatibleRig.cs.meta b/Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/Rigs/Vrm0XCompatibleRig.cs.meta
new file mode 100644
index 000000000..515a87b3b
--- /dev/null
+++ b/Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/Rigs/Vrm0XCompatibleRig.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: d1e0f212571bf3f41809f19c2d8f3211
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Assets/VRM10/Runtime/Components/Vrm10Runtime/OpenXRHandTracking.cs b/Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/Rigs/XR_EXT_hand_tracking.cs
similarity index 61%
rename from Assets/VRM10/Runtime/Components/Vrm10Runtime/OpenXRHandTracking.cs
rename to Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/Rigs/XR_EXT_hand_tracking.cs
index 9e622a739..a563e59bd 100644
--- a/Assets/VRM10/Runtime/Components/Vrm10Runtime/OpenXRHandTracking.cs
+++ b/Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/Rigs/XR_EXT_hand_tracking.cs
@@ -4,14 +4,23 @@ using UnityEngine;
 namespace UniVRM10
 {
     /// <summary>
-    /// TPose のときに XR_EXT_hand_tracking の joint が向いている向きを定義する。
+    /// XR_EXT_hand_tracking の joint を VRM-1.0 の TPose に当てはめたときの方向を定義します。
     /// 
-    /// https://registry.khronos.org/OpenXR/specs/1.0/html/xrspec.html#_conventions_of_hand_joints
+    /// * https://registry.khronos.org/OpenXR/specs/1.0/html/xrspec.html#_conventions_of_hand_joints
+    /// * https://github.com/vrm-c/vrm-specification/blob/master/specification/VRMC_vrm-1.0/tpose.ja.md
     /// 
-    /// Unityは左手系なので、X軸を反転させます。
     /// </summary>
-    public static class OpenXRHandTracking
+    public static class XR_EXT_hand_tracking
     {
+        /// <summary>
+        /// up vector と forward vector の外積により空間を算出して、回転を得ます。
+        /// 
+        /// OpenXR は右手系なのに対して Unityは左手系です。
+        /// 結果として、X軸が反転することに注意してください。
+        /// </summary>
+        /// <param name="up"></param>
+        /// <param name="forward"></param>
+        /// <returns></returns>
         public static Quaternion GetRotation(Vector3 up, Vector3 forward)
         {
             var xAxis = Vector3.Cross(up, forward).normalized;
@@ -20,11 +29,22 @@ namespace UniVRM10
         }
 
         public static Quaternion LeftHand = GetRotation(Vector3.up, Vector3.right);
-        public static Quaternion LeftThumb = GetRotation(Vector3.up, (Vector3.right + Vector3.forward).normalized);
         public static Quaternion RightHand = GetRotation(Vector3.up, Vector3.left);
-        public static Quaternion RightThumb = GetRotation(Vector3.up, (Vector3.left + Vector3.forward).normalized);
 
-        public static readonly Dictionary<HumanBodyBones, Quaternion> InitialRotations = new Dictionary<HumanBodyBones, Quaternion>()
+        /// <summary>
+        /// 親指は XZ 平面45度です。
+        /// </summary>
+        public static Quaternion LeftThumb = GetRotation((Vector3.forward + Vector3.left).normalized, (Vector3.right + Vector3.forward).normalized);
+
+        /// <summary>
+        /// 親指は XZ 平面45度です。
+        /// </summary>
+        public static Quaternion RightThumb = GetRotation((Vector3.forward + Vector3.right).normalized, (Vector3.left + Vector3.forward).normalized);
+
+        /// <summary>
+        /// VRM-1.0 の T-Pose の定義から各指はX軸と並行です。親指はXZ平面に45度です。
+        /// </summary>
+        public static IReadOnlyDictionary<HumanBodyBones, Quaternion> InitialRotations => new Dictionary<HumanBodyBones, Quaternion>()
         {
             // Left
             {HumanBodyBones.LeftHand, LeftHand},
diff --git a/Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/Rigs/XR_EXT_hand_tracking.cs.meta b/Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/Rigs/XR_EXT_hand_tracking.cs.meta
new file mode 100644
index 000000000..bd891171b
--- /dev/null
+++ b/Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/Rigs/XR_EXT_hand_tracking.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 551eba367636e4b45b222ce636a6adcf
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/Vrm10ControlBone.cs b/Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/Vrm10ControlBone.cs
index b3ec8fafd..8ab12e5d1 100644
--- a/Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/Vrm10ControlBone.cs
+++ b/Assets/VRM10/Runtime/Components/Vrm10Runtime/ControlRig/Vrm10ControlBone.cs
@@ -46,7 +46,7 @@ namespace UniVRM10
         private readonly Quaternion _initialTargetGlobalRotation;
         private readonly List<Vrm10ControlBone> _children = new List<Vrm10ControlBone>();
 
-        private Vrm10ControlBone(Transform controlTarget, HumanBodyBones boneType, Vrm10ControlBone parent, Dictionary<HumanBodyBones, Quaternion> initialRotations)
+        private Vrm10ControlBone(Transform controlTarget, HumanBodyBones boneType, Vrm10ControlBone parent, IReadOnlyDictionary<HumanBodyBones, Quaternion> controlRigInitialRotations)
         {
             if (boneType == HumanBodyBones.LastBone)
             {
@@ -61,9 +61,9 @@ namespace UniVRM10
             ControlTarget = controlTarget;
             // NOTE: bone name must be unique in the vrm instance.
             ControlBone = new GameObject($"{nameof(Vrm10ControlBone)}:{boneType.ToString()}").transform;
-            if (initialRotations != null)
+            if (controlRigInitialRotations != null)
             {
-                if (initialRotations.TryGetValue(boneType, out var rotation))
+                if (controlRigInitialRotations.TryGetValue(boneType, out var rotation))
                 {
                     ControlBone.rotation = rotation;
                 }
@@ -86,7 +86,7 @@ namespace UniVRM10
         /// <summary>
         /// 初期姿勢からの相対的な回転。
         /// 
-        /// VRM-0.X では localRotation と同じである。
+        /// VRM-0.X 互換リグでは localRotation と同じ値を示す。
         /// </summary>
         Quaternion NormalizedLocalRotation
         {
@@ -109,32 +109,32 @@ namespace UniVRM10
             }
         }
 
-        public static Vrm10ControlBone Build(UniHumanoid.Humanoid humanoid, Dictionary<HumanBodyBones, Quaternion> initialRotations, out Dictionary<HumanBodyBones, Vrm10ControlBone> boneMap)
+        public static Vrm10ControlBone Build(UniHumanoid.Humanoid humanoid, IReadOnlyDictionary<HumanBodyBones, Quaternion> controlRigInitialRotations, out Dictionary<HumanBodyBones, Vrm10ControlBone> boneMap)
         {
-            var hips = new Vrm10ControlBone(humanoid.Hips, HumanBodyBones.Hips, null, initialRotations);
+            var hips = new Vrm10ControlBone(humanoid.Hips, HumanBodyBones.Hips, null, controlRigInitialRotations);
             boneMap = new Dictionary<HumanBodyBones, Vrm10ControlBone>();
             boneMap.Add(HumanBodyBones.Hips, hips);
 
             foreach (Transform child in humanoid.Hips)
             {
-                BuildRecursively(humanoid, child, hips, initialRotations, boneMap);
+                BuildRecursively(humanoid, child, hips, controlRigInitialRotations, boneMap);
             }
 
             return hips;
         }
 
-        private static void BuildRecursively(UniHumanoid.Humanoid humanoid, Transform current, Vrm10ControlBone parent, Dictionary<HumanBodyBones, Quaternion> initialRotations, Dictionary<HumanBodyBones, Vrm10ControlBone> boneMap)
+        private static void BuildRecursively(UniHumanoid.Humanoid humanoid, Transform current, Vrm10ControlBone parent, IReadOnlyDictionary<HumanBodyBones, Quaternion> controlRigInitialRotations, Dictionary<HumanBodyBones, Vrm10ControlBone> boneMap)
         {
             if (humanoid.TryGetBoneForTransform(current, out var bone))
             {
-                var newBone = new Vrm10ControlBone(current, bone, parent, initialRotations);
+                var newBone = new Vrm10ControlBone(current, bone, parent, controlRigInitialRotations);
                 parent = newBone;
                 boneMap.Add(bone, newBone);
             }
 
             foreach (Transform child in current)
             {
-                BuildRecursively(humanoid, child, parent, initialRotations, boneMap);
+                BuildRecursively(humanoid, child, parent, controlRigInitialRotations, boneMap);
             }
         }
     }
diff --git a/Assets/VRM10/Runtime/Components/Vrm10Runtime/Vrm10Runtime.cs b/Assets/VRM10/Runtime/Components/Vrm10Runtime/Vrm10Runtime.cs
index a31b74134..0265e65b7 100644
--- a/Assets/VRM10/Runtime/Components/Vrm10Runtime/Vrm10Runtime.cs
+++ b/Assets/VRM10/Runtime/Components/Vrm10Runtime/Vrm10Runtime.cs
@@ -49,7 +49,7 @@ namespace UniVRM10
             }
         }
 
-        public Vrm10Runtime(Vrm10Instance target, ControlRigGenerationOption controlRigGenerationOption, Dictionary<HumanBodyBones, Quaternion> initialRotations = null)
+        public Vrm10Runtime(Vrm10Instance target, IReadOnlyDictionary<HumanBodyBones, Quaternion> controlRigInitialRotations)
         {
             m_target = target;
 
@@ -58,9 +58,9 @@ namespace UniVRM10
                 throw new Exception();
             }
 
-            if (controlRigGenerationOption != ControlRigGenerationOption.None)
+            if (controlRigInitialRotations != null)
             {
-                ControlRig = new Vrm10RuntimeControlRig(target.Humanoid, m_target.transform, controlRigGenerationOption, initialRotations);
+                ControlRig = new Vrm10RuntimeControlRig(target.Humanoid, m_target.transform, controlRigInitialRotations);
             }
             Constraints = target.GetComponentsInChildren<IVrm10Constraint>();
             LookAt = new Vrm10RuntimeLookAt(target.Vrm.LookAt, target.Humanoid, m_head, target.LookAtTargetType, target.Gaze);
diff --git a/Assets/VRM10/Runtime/Components/Vrm10Runtime/Vrm10RuntimeControlRig.cs b/Assets/VRM10/Runtime/Components/Vrm10Runtime/Vrm10RuntimeControlRig.cs
index 0edb375eb..681cf681d 100644
--- a/Assets/VRM10/Runtime/Components/Vrm10Runtime/Vrm10RuntimeControlRig.cs
+++ b/Assets/VRM10/Runtime/Components/Vrm10Runtime/Vrm10RuntimeControlRig.cs
@@ -25,17 +25,22 @@ namespace UniVRM10
         public float InitialHipsHeight { get; }
 
         /// <summary>
-        /// コンストラクタ。
-        /// humanoid は VRM T-Pose でなければならない。
+        /// humanoid に対して ControlRig を生成します
         /// </summary>
-        public Vrm10RuntimeControlRig(UniHumanoid.Humanoid humanoid, Transform vrmRoot, ControlRigGenerationOption option, Dictionary<HumanBodyBones, Quaternion> initialRotations)
+        /// <param name="humanoid">T-Pose である必要があります</param>
+        /// <param name="vrmRoot"></param>
+        /// <param name="controlRigInitialRotations">ControlRigの各ボーンの初期回転を表します</param>
+        public Vrm10RuntimeControlRig(UniHumanoid.Humanoid humanoid, Transform vrmRoot, IReadOnlyDictionary<HumanBodyBones, Quaternion> controlRigInitialRotations)
         {
-            if (option == ControlRigGenerationOption.None) return;
+            if (controlRigInitialRotations == null)
+            {
+                throw new ArgumentNullException();
+            }
 
             _controlRigRoot = new GameObject("Runtime Control Rig").transform;
             _controlRigRoot.SetParent(vrmRoot);
 
-            _hipBone = Vrm10ControlBone.Build(humanoid, initialRotations, out _bones);
+            _hipBone = Vrm10ControlBone.Build(humanoid, controlRigInitialRotations, out _bones);
             _hipBone.ControlBone.SetParent(_controlRigRoot);
 
             InitialHipsHeight = _hipBone.ControlTarget.position.y;
diff --git a/Assets/VRM10/Runtime/IO/Vrm10.cs b/Assets/VRM10/Runtime/IO/Vrm10.cs
index 2d2bed77b..5f5ef9448 100644
--- a/Assets/VRM10/Runtime/IO/Vrm10.cs
+++ b/Assets/VRM10/Runtime/IO/Vrm10.cs
@@ -39,7 +39,6 @@ namespace UniVRM10
             string path,
             bool canLoadVrm0X = true,
             ControlRigGenerationOption controlRigGenerationOption = ControlRigGenerationOption.Generate,
-            Dictionary<HumanBodyBones, Quaternion> initialRotations = null,
             bool showMeshes = true,
             IAwaitCaller awaitCaller = null,
             IMaterialDescriptorGenerator materialGenerator = null,
@@ -58,7 +57,6 @@ namespace UniVRM10
                 System.IO.File.ReadAllBytes(path),
                 canLoadVrm0X,
                 controlRigGenerationOption,
-                initialRotations,
                 showMeshes,
                 awaitCaller,
                 materialGenerator,
@@ -85,7 +83,6 @@ namespace UniVRM10
             byte[] bytes,
             bool canLoadVrm0X = true,
             ControlRigGenerationOption controlRigGenerationOption = ControlRigGenerationOption.Generate,
-            Dictionary<HumanBodyBones, Quaternion> initialRotations = null,
             bool showMeshes = true,
             IAwaitCaller awaitCaller = null,
             IMaterialDescriptorGenerator materialGenerator = null,
@@ -104,7 +101,6 @@ namespace UniVRM10
                 bytes,
                 canLoadVrm0X,
                 controlRigGenerationOption,
-                initialRotations,
                 showMeshes,
                 awaitCaller,
                 materialGenerator,
@@ -117,7 +113,6 @@ namespace UniVRM10
             byte[] bytes,
             bool canLoadVrm0X,
             ControlRigGenerationOption controlRigGenerationOption,
-            Dictionary<HumanBodyBones, Quaternion> initialRotations,
             bool showMeshes,
             IAwaitCaller awaitCaller,
             IMaterialDescriptorGenerator materialGenerator,
@@ -136,7 +131,6 @@ namespace UniVRM10
                 var instance = await TryLoadingAsVrm10Async(
                     gltfData,
                     controlRigGenerationOption,
-                    initialRotations,
                     showMeshes,
                     awaitCaller,
                     materialGenerator,
@@ -162,7 +156,6 @@ namespace UniVRM10
                 var migratedInstance = await TryMigratingFromVrm0XAsync(
                     gltfData,
                     controlRigGenerationOption,
-                    initialRotations,
                     showMeshes,
                     awaitCaller,
                     materialGenerator,
@@ -186,7 +179,6 @@ namespace UniVRM10
         private static async Task<Vrm10Instance> TryLoadingAsVrm10Async(
             GltfData gltfData,
             ControlRigGenerationOption controlRigGenerationOption,
-            Dictionary<HumanBodyBones, Quaternion> initialRotations,
             bool showMeshes,
             IAwaitCaller awaitCaller,
             IMaterialDescriptorGenerator materialGenerator,
@@ -212,7 +204,6 @@ namespace UniVRM10
                 vrm10Data,
                 null,
                 controlRigGenerationOption,
-                initialRotations,
                 showMeshes,
                 awaitCaller,
                 materialGenerator,
@@ -223,7 +214,6 @@ namespace UniVRM10
         private static async Task<Vrm10Instance> TryMigratingFromVrm0XAsync(
             GltfData gltfData,
             ControlRigGenerationOption controlRigGenerationOption,
-            Dictionary<HumanBodyBones, Quaternion> initialRotations,
             bool showMeshes,
             IAwaitCaller awaitCaller,
             IMaterialDescriptorGenerator materialGenerator,
@@ -251,7 +241,6 @@ namespace UniVRM10
                     migratedVrm10Data,
                     migrationData,
                     controlRigGenerationOption,
-                    initialRotations,
                     showMeshes,
                     awaitCaller,
                     materialGenerator,
@@ -269,7 +258,6 @@ namespace UniVRM10
             Vrm10Data vrm10Data,
             MigrationData migrationData,
             ControlRigGenerationOption controlRigGenerationOption,
-            Dictionary<HumanBodyBones, Quaternion> initialRotations,
             bool showMeshes,
             IAwaitCaller awaitCaller,
             IMaterialDescriptorGenerator materialGenerator,
@@ -287,7 +275,7 @@ namespace UniVRM10
                 throw new ArgumentNullException(nameof(vrm10Data));
             }
 
-            using (var loader = new Vrm10Importer(vrm10Data, controlRigGenerationOption: controlRigGenerationOption, initialRotations: initialRotations, materialGenerator: materialGenerator))
+            using (var loader = new Vrm10Importer(vrm10Data, controlRigGenerationOption.ToInitialRotations(), materialGenerator: materialGenerator))
             {
                 // 1. Load meta information if callback was available.
                 if (vrmMetaInformationCallback != null)
diff --git a/Assets/VRM10/Runtime/IO/Vrm10Importer.cs b/Assets/VRM10/Runtime/IO/Vrm10Importer.cs
index 0e23ba5e8..8d42eea33 100644
--- a/Assets/VRM10/Runtime/IO/Vrm10Importer.cs
+++ b/Assets/VRM10/Runtime/IO/Vrm10Importer.cs
@@ -18,8 +18,7 @@ namespace UniVRM10
         private readonly Vrm10Data m_vrm;
         /// VrmLib.Model の オブジェクトと UnityEngine.Object のマッピングを記録する
         private readonly ModelMap m_map = new ModelMap();
-        private readonly ControlRigGenerationOption m_controlRigGenerationOption;
-        private readonly Dictionary<HumanBodyBones, Quaternion> m_initialRotations;
+        private readonly IReadOnlyDictionary<HumanBodyBones, Quaternion> m_controlRigInitialRotations;
 
         private VrmLib.Model m_model;
         private IReadOnlyDictionary<SubAssetKey, UnityEngine.Object> m_externalMap;
@@ -29,11 +28,11 @@ namespace UniVRM10
 
         public Vrm10Importer(
             Vrm10Data vrm,
+            IReadOnlyDictionary<HumanBodyBones, Quaternion> controlRigInitialRotations,
             IReadOnlyDictionary<SubAssetKey, UnityEngine.Object> externalObjectMap = null,
             ITextureDeserializer textureDeserializer = null,
-            IMaterialDescriptorGenerator materialGenerator = null,
-            ControlRigGenerationOption controlRigGenerationOption = ControlRigGenerationOption.None,
-            Dictionary<HumanBodyBones, Quaternion> initialRotations = null)
+            IMaterialDescriptorGenerator materialGenerator = null
+            )
             : base(vrm.Data, externalObjectMap, textureDeserializer)
         {
             if (vrm == null)
@@ -41,8 +40,7 @@ namespace UniVRM10
                 throw new ArgumentNullException("vrm");
             }
             m_vrm = vrm;
-            m_controlRigGenerationOption = controlRigGenerationOption;
-            m_initialRotations = initialRotations;
+            m_controlRigInitialRotations = controlRigInitialRotations;
 
             TextureDescriptorGenerator = new Vrm10TextureDescriptorGenerator(Data);
             MaterialDescriptorGenerator = materialGenerator ?? new BuiltInVrm10MaterialDescriptorGenerator();
@@ -249,7 +247,7 @@ namespace UniVRM10
 
             // VrmController
             var controller = Root.AddComponent<Vrm10Instance>();
-            controller.InitializeAtRuntime(m_controlRigGenerationOption, m_initialRotations);
+            controller.InitializeAtRuntime(m_controlRigInitialRotations);
             controller.enabled = false;
 
             // vrm
diff --git a/Assets/VRM10/Tests.PlayMode/MaterialTests.cs b/Assets/VRM10/Tests.PlayMode/MaterialTests.cs
index 0dcc7b4ba..19f41039b 100644
--- a/Assets/VRM10/Tests.PlayMode/MaterialTests.cs
+++ b/Assets/VRM10/Tests.PlayMode/MaterialTests.cs
@@ -45,7 +45,7 @@ namespace UniVRM10.Test
         private (GameObject, IReadOnlyList<VRMShaders.MaterialFactory.MaterialLoadInfo>) ToUnity(Vrm10Data data)
         {
             // Model => Unity
-            using (var loader = new Vrm10Importer(data))
+            using (var loader = new Vrm10Importer(data, null))
             {
                 var loaded = loader.Load();
                 return (loaded.gameObject, loader.MaterialFactory.Materials);
diff --git a/Assets/VRM10/Tests/ApiSampleTests.cs b/Assets/VRM10/Tests/ApiSampleTests.cs
index f306c7990..a53b0dfdb 100644
--- a/Assets/VRM10/Tests/ApiSampleTests.cs
+++ b/Assets/VRM10/Tests/ApiSampleTests.cs
@@ -21,7 +21,7 @@ namespace UniVRM10.Test
 
         GameObject BuildGameObject(Vrm10Data data, bool showMesh)
         {
-            using (var loader = new Vrm10Importer(data))
+            using (var loader = new Vrm10Importer(data, null))
             {
                 var loaded = loader.Load();
                 if (showMesh)
diff --git a/Assets/VRM10/Tests/ExpressionTests.cs b/Assets/VRM10/Tests/ExpressionTests.cs
index 8b8be849b..99e832566 100644
--- a/Assets/VRM10/Tests/ExpressionTests.cs
+++ b/Assets/VRM10/Tests/ExpressionTests.cs
@@ -32,7 +32,7 @@ namespace UniVRM10.Test
             controller.Vrm.Expression.Aa.MaterialColorBindings = src.ToArray();
 
             // ok if no exception
-            var r = new Vrm10Runtime(controller, ControlRigGenerationOption.None);
+            var r = new Vrm10Runtime(controller, null);
         }
 
         [Test]
@@ -56,7 +56,7 @@ namespace UniVRM10.Test
             controller.Vrm.Expression.Aa.MaterialUVBindings = src.ToArray();
 
             // ok if no exception
-            var r = new Vrm10Runtime(controller, ControlRigGenerationOption.None);
+            var r = new Vrm10Runtime(controller, null);
         }
     }
 }
diff --git a/Assets/VRM10/Tests/LoadTests.cs b/Assets/VRM10/Tests/LoadTests.cs
index 652e5a146..ca2a4ac49 100644
--- a/Assets/VRM10/Tests/LoadTests.cs
+++ b/Assets/VRM10/Tests/LoadTests.cs
@@ -19,7 +19,7 @@ namespace UniVRM10.Test
                 // empty thumbnail name
                 vrm1Data.Data.GLTF.images[index].name = null;
 
-                using (var loader = new Vrm10Importer(vrm1Data))
+                using (var loader = new Vrm10Importer(vrm1Data, null))
                 {
                     loader.LoadAsync(new VRMShaders.ImmediateCaller()).Wait();
                 }