diff --git a/challenges/cw.py b/challenges/cw.py
index 572f3d2..73cb10f 100644
--- a/challenges/cw.py
+++ b/challenges/cw.py
@@ -62,7 +62,8 @@
     '!': '1,1,1,0,1,0,1,1,1,0,1,0,1,1,1,0,1,1,1,0',
     ' ': '0,0,0',
     '-': '1,1,1,0,1,0,1,0,1,0,1,0,1,1,1,0',
-    ':': '1,1,1,0,1,1,1,0,1,1,1,0,1,0,1,0,1,0'
+    ':': '1,1,1,0,1,1,1,0,1,1,1,0,1,0,1,0,1,0',
+    '_': '1,0,1,0,1,1,1,0,1,1,1,0,1,0,1,1,1,0'
 }
 
 morse_code = '0,'