diff --git a/git_command.py b/git_command.py
index 7ff1aba..d56ad0a 100644
--- a/git_command.py
+++ b/git_command.py
@@ -68,6 +68,30 @@
     return fun
 git = _GitCall()
 
+_git_version = None
+
+def git_require(min_version, fail=False):
+  global _git_version
+
+  if _git_version is None:
+    ver_str = git.version()
+    if ver_str.startswith('git version '):
+      _git_version = tuple(
+        map(lambda x: int(x),
+          ver_str[len('git version '):].strip().split('.')[0:3]
+        ))
+    else:
+      print >>sys.stderr, 'fatal: "%s" unsupported' % ver_str
+      sys.exit(1)
+
+  if min_version <= _git_version:
+    return True
+  if fail:
+    need = '.'.join(map(lambda x: str(x), min_version))
+    print >>sys.stderr, 'fatal: git %s or later required' % need
+    sys.exit(1)
+  return False
+
 class GitCommand(object):
   def __init__(self,
                project,
diff --git a/subcmds/init.py b/subcmds/init.py
index 5ba4d79..fbc406e 100644
--- a/subcmds/init.py
+++ b/subcmds/init.py
@@ -20,7 +20,7 @@
 from command import InteractiveCommand, MirrorSafeCommand
 from error import ManifestParseError
 from project import SyncBuffer
-from git_command import git, MIN_GIT_VERSION
+from git_command import git_require, MIN_GIT_VERSION
 
 class Init(InteractiveCommand, MirrorSafeCommand):
   common = True
@@ -85,19 +85,6 @@
                  dest='no_repo_verify', action='store_true',
                  help='do not verify repo source code')
 
-  def _CheckGitVersion(self):
-    ver_str = git.version()
-    if not ver_str.startswith('git version '):
-      print >>sys.stderr, 'error: "%s" unsupported' % ver_str
-      sys.exit(1)
-
-    ver_str = ver_str[len('git version '):].strip()
-    ver_act = tuple(map(lambda x: int(x), ver_str.split('.')[0:3]))
-    if ver_act < MIN_GIT_VERSION:
-      need = '.'.join(map(lambda x: str(x), MIN_GIT_VERSION))
-      print >>sys.stderr, 'fatal: git %s or later required' % need
-      sys.exit(1)
-
   def _SyncManifest(self, opt):
     m = self.manifest.manifestProject
     is_new = not m.Exists
@@ -214,7 +201,7 @@
       gc.SetString('color.ui', 'auto')
 
   def Execute(self, opt, args):
-    self._CheckGitVersion()
+    git_require(MIN_GIT_VERSION, fail=True)
     self._SyncManifest(opt)
     self._LinkManifest(opt.manifest_name)