diff --git a/engine/package.json b/engine/package.json
index d1008f59..fa0b4e6d 100644
--- a/engine/package.json
+++ b/engine/package.json
@@ -1,6 +1,6 @@
 {
     "name": "goban-engine",
-    "version": "8.3.13",
+    "version": "8.3.15",
     "description": "",
     "main": "build/goban-engine.js",
     "types": "build/engine/index.d.ts",
diff --git a/package.json b/package.json
index 7b579a30..b378072e 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
     "name": "goban",
-    "version": "8.3.13",
+    "version": "8.3.15",
     "description": "",
     "main": "build/goban.js",
     "types": "build/src/index.d.ts",
diff --git a/src/Goban/themes/GobanTheme.ts b/src/Goban/themes/GobanTheme.ts
index f129d244..e7b7a7ad 100644
--- a/src/Goban/themes/GobanTheme.ts
+++ b/src/Goban/themes/GobanTheme.ts
@@ -16,6 +16,8 @@
 
 import { GobanBase } from "../../GobanBase";
 
+let last_def_uid = 0;
+
 export interface GobanThemeBackgroundCSS {
     "background-color"?: string;
     "background-image"?: string;
@@ -103,7 +105,7 @@ export class GobanTheme {
         _deferredRenderCallback: () => void,
     ): string[] {
         const ret = [];
-        const key = `black-${radius}`;
+        const key = this.def_uid(`black-${radius}`);
         ret.push(key);
 
         defs.appendChild(
@@ -131,7 +133,7 @@ export class GobanTheme {
         _deferredRenderCallback: () => void,
     ): string[] {
         const ret = [];
-        const key = `white-${radius}`;
+        const key = this.def_uid(`white-${radius}`);
         ret.push(key);
         defs.appendChild(
             this.renderSVG(
@@ -437,4 +439,10 @@ export class GobanTheme {
 
         return stone;
     }
+
+    public def_uid(base: string): string {
+        const uid = last_def_uid++;
+
+        return `${base}-${uid}`;
+    }
 }
diff --git a/src/Goban/themes/image_stones.ts b/src/Goban/themes/image_stones.ts
index ec3a0263..c8366dd3 100644
--- a/src/Goban/themes/image_stones.ts
+++ b/src/Goban/themes/image_stones.ts
@@ -267,17 +267,18 @@ export default function (THEMES: ThemesInterface) {
             _seed: number,
             deferredRenderCallback: () => void,
         ): string[] {
+            const id = this.def_uid(`anime-black-${radius}`);
             defs.append(
                 this.renderSVG(
                     {
-                        id: `anime-black-${radius}`,
+                        id,
                         url: getCDNReleaseBase() + "/img/anime_black.svg",
                     },
                     radius,
                 ),
             );
 
-            return [`anime-black-${radius}`];
+            return [id];
         }
 
         public override preRenderWhiteSVG(
@@ -286,17 +287,18 @@ export default function (THEMES: ThemesInterface) {
             _seed: number,
             deferredRenderCallback: () => void,
         ): string[] {
+            const id = this.def_uid(`anime-white-${radius}`);
             defs.append(
                 this.renderSVG(
                     {
-                        id: `anime-white-${radius}`,
+                        id,
                         url: getCDNReleaseBase() + "/img/anime_white.svg",
                     },
                     radius,
                 ),
             );
 
-            return [`anime-white-${radius}`];
+            return [id];
         }
     }
 
@@ -416,17 +418,18 @@ export default function (THEMES: ThemesInterface) {
                 return super.preRenderBlackSVG(defs, radius, _seed, deferredRenderCallback);
             }
 
+            const id = this.def_uid(`custom-black-${radius}`);
             defs.append(
                 this.renderSVG(
                     {
-                        id: `custom-black-${radius}`,
+                        id,
                         url: callbacks.customBlackStoneUrl(),
                     },
                     radius,
                 ),
             );
 
-            return [`custom-black-${radius}`];
+            return [id];
         }
 
         public override preRenderWhiteSVG(
@@ -439,17 +442,18 @@ export default function (THEMES: ThemesInterface) {
                 return super.preRenderWhiteSVG(defs, radius, _seed, deferredRenderCallback);
             }
 
+            const id = this.def_uid(`custom-white-${radius}`);
             defs.append(
                 this.renderSVG(
                     {
-                        id: `custom-white-${radius}`,
+                        id,
                         url: callbacks.customWhiteStoneUrl(),
                     },
                     radius,
                 ),
             );
 
-            return [`custom-white-${radius}`];
+            return [id];
         }
     }
 
diff --git a/src/Goban/themes/plain_stones.ts b/src/Goban/themes/plain_stones.ts
index 2ded82d8..11137d3a 100644
--- a/src/Goban/themes/plain_stones.ts
+++ b/src/Goban/themes/plain_stones.ts
@@ -129,7 +129,7 @@ export default function (THEMES: ThemesInterface) {
             _deferredRenderCallback: () => void,
         ): string[] {
             const ret = [];
-            const key = `plain-black-${radius}`;
+            const key = this.def_uid(`plain-black-${radius}`);
             ret.push(key);
 
             let color: string | undefined = this.getBlackStoneColor();
@@ -174,7 +174,7 @@ export default function (THEMES: ThemesInterface) {
             _deferredRenderCallback: () => void,
         ): string[] {
             const ret = [];
-            const key = `plain-white-${radius}`;
+            const key = this.def_uid(`plain-white-${radius}`);
             ret.push(key);
             defs.appendChild(
                 this.renderSVG(
diff --git a/src/Goban/themes/rendered_stones.ts b/src/Goban/themes/rendered_stones.ts
index e2510d34..f39f3ed7 100644
--- a/src/Goban/themes/rendered_stones.ts
+++ b/src/Goban/themes/rendered_stones.ts
@@ -533,7 +533,7 @@ export default function (THEMES: ThemesInterface) {
             _deferredRenderCallback: () => void,
         ): string[] {
             const ret = [];
-            const key = `black-slate-${radius}`;
+            const key = this.def_uid(`black-slate-${radius}`);
             ret.push(key);
             defs.appendChild(
                 this.renderSVG(
@@ -600,7 +600,7 @@ export default function (THEMES: ThemesInterface) {
             let s = seed;
 
             for (let i = 0; i < 20; ++i) {
-                const key = `white-shell-${i}-${radius}`;
+                const key = this.def_uid(`white-shell-${i}-${radius}`);
                 ret.push(key);
 
                 const stone = this.renderSVG(
@@ -759,7 +759,7 @@ export default function (THEMES: ThemesInterface) {
             _seed: number,
             _deferredRenderCallback: () => void,
         ): string[] {
-            const key = `black-glass-${radius}`;
+            const key = this.def_uid(`black-glass-${radius}`);
             const stone = this.renderSVG(
                 {
                     id: key,
@@ -795,7 +795,7 @@ export default function (THEMES: ThemesInterface) {
             _seed: number,
             _deferredRenderCallback: () => void,
         ): string[] {
-            const key = `white-glass-${radius}`;
+            const key = this.def_uid(`white-glass-${radius}`);
             const stone = this.renderSVG(
                 {
                     id: key,
@@ -878,7 +878,7 @@ export default function (THEMES: ThemesInterface) {
             _seed: number,
             _deferredRenderCallback: () => void,
         ): string[] {
-            const key = `black-worn-glass-${radius}`;
+            const key = this.def_uid(`black-worn-glass-${radius}`);
             const stone = this.renderSVG(
                 {
                     id: key,
@@ -914,7 +914,7 @@ export default function (THEMES: ThemesInterface) {
             _seed: number,
             _deferredRenderCallback: () => void,
         ): string[] {
-            const key = `white-worn-glass-${radius}`;
+            const key = this.def_uid(`white-worn-glass-${radius}`);
             const stone = this.renderSVG(
                 {
                     id: key,
@@ -995,7 +995,7 @@ export default function (THEMES: ThemesInterface) {
             _seed: number,
             _deferredRenderCallback: () => void,
         ): string[] {
-            const key = `black-night-${radius}`;
+            const key = this.def_uid(`black-night-${radius}`);
             const stone = this.renderSVG(
                 {
                     id: key,
@@ -1031,7 +1031,7 @@ export default function (THEMES: ThemesInterface) {
             _seed: number,
             _deferredRenderCallback: () => void,
         ): string[] {
-            const key = `white-night-${radius}`;
+            const key = this.def_uid(`white-night-${radius}`);
             const stone = this.renderSVG(
                 {
                     id: key,