diff --git a/.changeset/strong-dryers-pay.md b/.changeset/strong-dryers-pay.md
new file mode 100644
index 000000000..495cde202
--- /dev/null
+++ b/.changeset/strong-dryers-pay.md
@@ -0,0 +1,5 @@
+---
+'mermaid': patch
+---
+
+fix: correctly render non-directional lines for '---' in block diagrams
diff --git a/cypress/integration/rendering/block.spec.js b/cypress/integration/rendering/block.spec.js
index f01d59375..180c0093d 100644
--- a/cypress/integration/rendering/block.spec.js
+++ b/cypress/integration/rendering/block.spec.js
@@ -393,6 +393,17 @@ describe('Block diagram', () => {
   overflow:3
   short:1
   also_overflow:2
+`,
+      {}
+    );
+  });
+
+  it('BL31: edge without arrow syntax should render with no arrowheads', () => {
+    imgSnapshotTest(
+      `block-beta
+  a
+  b
+  a --- b
 `,
       {}
     );
diff --git a/packages/mermaid/src/diagrams/block/blockDB.ts b/packages/mermaid/src/diagrams/block/blockDB.ts
index 39a8b47a0..b291be61e 100644
--- a/packages/mermaid/src/diagrams/block/blockDB.ts
+++ b/packages/mermaid/src/diagrams/block/blockDB.ts
@@ -238,13 +238,15 @@ export function edgeTypeStr2Type(typeStr: string): string {
 }
 
 export function edgeStrToEdgeData(typeStr: string): string {
-  switch (typeStr.trim()) {
-    case '--x':
+  switch (typeStr.replace(/^[\s-]+|[\s-]+$/g, '')) {
+    case 'x':
       return 'arrow_cross';
-    case '--o':
+    case 'o':
       return 'arrow_circle';
-    default:
+    case '>':
       return 'arrow_point';
+    default:
+      return '';
   }
 }