diff --git a/Assets/VRM10/Runtime/Migration/MigrationMToon.cs b/Assets/VRM10/Runtime/Migration/MigrationMToon.cs
index 206a81799..514499b14 100644
--- a/Assets/VRM10/Runtime/Migration/MigrationMToon.cs
+++ b/Assets/VRM10/Runtime/Migration/MigrationMToon.cs
@@ -5,6 +5,7 @@ using UniGLTF;
 using UniGLTF.Extensions.VRMC_materials_mtoon;
 using UniJSON;
 using UnityEngine;
+using VRMShaders.VRM10.MToon10.Runtime;
 using ColorSpace = VRMShaders.ColorSpace;
 using RenderMode = MToon.RenderMode;
 
@@ -419,9 +420,15 @@ namespace UniVRM10
                 }
 
                 // Light
-                dst.GiIntensityFactor = mtoon.Definition.Lighting.LightingInfluence.GiIntensityValue;
-                dst.ShadingShiftFactor = mtoon.Definition.Lighting.LitAndShadeMixing.ShadingShiftValue;
-                dst.ShadingToonyFactor = mtoon.Definition.Lighting.LitAndShadeMixing.ShadingToonyValue;
+                dst.GiIntensityFactor = MToonMigrator.MigrateToGiEqualization(mtoon.Definition.Lighting.LightingInfluence.GiIntensityValue);
+                dst.ShadingToonyFactor = MToonMigrator.MigrateToShadingToony(
+                    mtoon.Definition.Lighting.LitAndShadeMixing.ShadingToonyValue,
+                    mtoon.Definition.Lighting.LitAndShadeMixing.ShadingShiftValue
+                );
+                dst.ShadingShiftFactor = MToonMigrator.MigrateToShadingShift(
+                    mtoon.Definition.Lighting.LitAndShadeMixing.ShadingToonyValue,
+                    mtoon.Definition.Lighting.LitAndShadeMixing.ShadingShiftValue
+                );
                 if (mtoon.TextureIndexMap.BumpMap.HasValue)
                 {
                     gltfMaterial.normalTexture = new glTFMaterialNormalTextureInfo
diff --git a/Assets/VRM10/Runtime/VRM10.asmdef b/Assets/VRM10/Runtime/VRM10.asmdef
index 845518186..2edebf50b 100644
--- a/Assets/VRM10/Runtime/VRM10.asmdef
+++ b/Assets/VRM10/Runtime/VRM10.asmdef
@@ -6,6 +6,7 @@
         "UniGLTF",
         "VRMShaders.GLTF.IO.Runtime",
         "VRMShaders.VRM10.Format.Runtime",
+        "VRMShaders.VRM10.MToon10.Runtime",
         "UniHumanoid"
     ],
     "optionalUnityReferences": [],
diff --git a/Assets/VRMShaders/VRM10/MToon10/Runtime/Migrator.cs b/Assets/VRMShaders/VRM10/MToon10/Runtime/Migrator.cs
new file mode 100644
index 000000000..eda2462bc
--- /dev/null
+++ b/Assets/VRMShaders/VRM10/MToon10/Runtime/Migrator.cs
@@ -0,0 +1,48 @@
+using UnityEngine;
+
+namespace VRMShaders.VRM10.MToon10.Runtime
+{
+    /// <summary>
+    /// Migrate from VRM 0.x MToon to VRM 1.0 vrmc_materials_mtoon
+    /// </summary>
+    public sealed class MToonMigrator
+    {
+        /// <summary>
+        /// mtoon.shadingToonyFactor
+        /// </summary>
+        public static float MigrateToShadingToony(float shadingToony0X, float shadingShift0X)
+        {
+            var (rangeMin, rangeMax) = GetShadingRange0X(shadingToony0X, shadingShift0X);
+
+            // new shadingToony is the margin of range.
+            return Mathf.Clamp((2.0f - (rangeMax - rangeMin)) * 0.5f, 0, 1);
+        }
+
+        /// <summary>
+        /// mtoon.shadingShiftFactor
+        /// </summary>
+        public static float MigrateToShadingShift(float shadingToony0X, float shadingShift0X)
+        {
+            var (rangeMin, rangeMax) = GetShadingRange0X(shadingToony0X, shadingShift0X);
+
+            // new shadingShift is the center of range.
+            return Mathf.Clamp((rangeMax - rangeMin) * 0.5f, -1, +1);
+        }
+
+        /// <summary>
+        /// mtoon.giEqualizationFactor
+        /// </summary>
+        public static float MigrateToGiEqualization(float giIntensity0X)
+        {
+            return Mathf.Clamp01(1 - giIntensity0X);
+        }
+
+        private static (float min, float max) GetShadingRange0X(float shadingToony0X, float shadingShift0X)
+        {
+            var rangeMin = shadingShift0X;
+            var rangeMax = Mathf.Lerp(1, shadingShift0X, shadingToony0X);
+
+            return (rangeMin, rangeMax);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Assets/VRMShaders/VRM10/MToon10/Runtime/Migrator.cs.meta b/Assets/VRMShaders/VRM10/MToon10/Runtime/Migrator.cs.meta
new file mode 100644
index 000000000..d9150d358
--- /dev/null
+++ b/Assets/VRMShaders/VRM10/MToon10/Runtime/Migrator.cs.meta
@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: 920db45663454ba8b8debaf2aeb7f5c9
+timeCreated: 1623217316
\ No newline at end of file