diff --git a/IPython/nbformat/v2/nbjson.py b/IPython/nbformat/v2/nbjson.py
index e207466..d60e95f 100644
--- a/IPython/nbformat/v2/nbjson.py
+++ b/IPython/nbformat/v2/nbjson.py
@@ -51,7 +51,7 @@ class JSONWriter(NotebookWriter):
 
     def writes(self, nb, **kwargs):
         kwargs['cls'] = BytesEncoder
-        kwargs['indent'] = 4
+        kwargs['indent'] = 1
         kwargs['sort_keys'] = True
         if kwargs.pop('split_lines', True):
             nb = split_lines(copy.deepcopy(nb))