diff --git a/syntax/madoko.vim b/syntax/madoko.vim
index 298ae7d..0b5f78c 100644
--- a/syntax/madoko.vim
+++ b/syntax/madoko.vim
@@ -4,7 +4,10 @@ endif
 
 syn case ignore
 
-syn region madokoTildeBlock "\v^~*$"
+" This isn't quite accurate because it doesn't match the number of ~ at the start and end, as the
+" Madoko spec. indicates. However, I don't think that this can be done with Vim syntax highlighting,
+" so this may be the best approximation.
+syn region madokoTildeBlock start="\v^~*$" end="\v^~*$"
 
 syn include @tex syntax/tex.vim
 syn region madokoMath start="\v\$" end="\v\$" contains=@tex keepend