diff --git a/docs/adding-new-shape/Readme.md b/docs/adding-new-shape.md
similarity index 97%
rename from docs/adding-new-shape/Readme.md
rename to docs/adding-new-shape.md
index 7d2c6eb811..b409d7c806 100644
--- a/docs/adding-new-shape/Readme.md
+++ b/docs/adding-new-shape.md
@@ -2,7 +2,7 @@
 >
 > ## THIS IS AN AUTOGENERATED FILE. DO NOT EDIT.
 >
-> ## Please edit the corresponding file in [/packages/mermaid/src/docs/adding-new-shape/Readme.md](../../packages/mermaid/src/docs/adding-new-shape/Readme.md).
+> ## Please edit the corresponding file in [/packages/mermaid/src/docs/adding-new-shape.md](../packages/mermaid/src/docs/adding-new-shape.md).
 
 # Custom SVG Shapes Library
 
@@ -126,7 +126,9 @@ To add a new shape:
 
   const shapes = {
     ...,
-    myNewShape,
+    'my-new-shape': myNewShape,
+    // Shortened alias (if any).
+    'm-nsh': myNewShape
   };
   ```
 
diff --git a/packages/mermaid/src/diagrams/flowchart/flowDb.ts b/packages/mermaid/src/diagrams/flowchart/flowDb.ts
index 4785b27792..c94dffa498 100644
--- a/packages/mermaid/src/diagrams/flowchart/flowDb.ts
+++ b/packages/mermaid/src/diagrams/flowchart/flowDb.ts
@@ -133,7 +133,7 @@ export const addVertex = function (
     }
     // console.log('yamlData', yamlData);
     const doc = yaml.load(yamlData, { schema: yaml.JSON_SCHEMA }) as NodeMetaData;
-    if (doc.shape && doc.shape !== doc.shape.toLowerCase()) {
+    if (doc.shape && (doc.shape !== doc.shape.toLowerCase() || doc.shape.includes('_'))) {
       throw new Error(`No such shape: ${doc.shape}. Shape names should be lowercase.`);
     }
 
diff --git a/packages/mermaid/src/docs/adding-new-shape/Readme.md b/packages/mermaid/src/docs/adding-new-shape.md
similarity index 98%
rename from packages/mermaid/src/docs/adding-new-shape/Readme.md
rename to packages/mermaid/src/docs/adding-new-shape.md
index cf8f9b3fed..b04d5f7941 100644
--- a/packages/mermaid/src/docs/adding-new-shape/Readme.md
+++ b/packages/mermaid/src/docs/adding-new-shape.md
@@ -120,7 +120,9 @@ To add a new shape:
 
   const shapes = {
     ...,
-    myNewShape,
+    'my-new-shape': myNewShape,
+    // Shortened alias (if any).
+    'm-nsh': myNewShape
   };
   ```