diff --git a/dlls/msvcr100/msvcr100.spec b/dlls/msvcr100/msvcr100.spec
index b6b10ba0655..f9f432fc936 100644
--- a/dlls/msvcr100/msvcr100.spec
+++ b/dlls/msvcr100/msvcr100.spec
@@ -986,7 +986,7 @@
 @ stub _ismbchira_l
 @ cdecl _ismbckata(long)
 @ stub _ismbckata_l
-@ stub _ismbcl0(long)
+@ cdecl _ismbcl0(long)
 @ stub _ismbcl0_l
 @ stub _ismbcl1(long)
 @ stub _ismbcl1_l
diff --git a/dlls/msvcr110/msvcr110.spec b/dlls/msvcr110/msvcr110.spec
index b36cb3a04bd..01793c77b4f 100644
--- a/dlls/msvcr110/msvcr110.spec
+++ b/dlls/msvcr110/msvcr110.spec
@@ -1332,7 +1332,7 @@
 @ stub _ismbchira_l
 @ cdecl _ismbckata(long)
 @ stub _ismbckata_l
-@ stub _ismbcl0(long)
+@ cdecl _ismbcl0(long)
 @ stub _ismbcl0_l
 @ stub _ismbcl1(long)
 @ stub _ismbcl1_l
diff --git a/dlls/msvcr120/msvcr120.spec b/dlls/msvcr120/msvcr120.spec
index 77daf09ed8c..a6a08ad418d 100644
--- a/dlls/msvcr120/msvcr120.spec
+++ b/dlls/msvcr120/msvcr120.spec
@@ -1337,7 +1337,7 @@
 @ stub _ismbchira_l
 @ cdecl _ismbckata(long)
 @ stub _ismbckata_l
-@ stub _ismbcl0(long)
+@ cdecl _ismbcl0(long)
 @ stub _ismbcl0_l
 @ stub _ismbcl1(long)
 @ stub _ismbcl1_l
diff --git a/dlls/msvcr70/msvcr70.spec b/dlls/msvcr70/msvcr70.spec
index bbfbea1f2f2..fb5aa9d791a 100644
--- a/dlls/msvcr70/msvcr70.spec
+++ b/dlls/msvcr70/msvcr70.spec
@@ -381,7 +381,7 @@
 @ cdecl _ismbcgraph(long)
 @ cdecl _ismbchira(long)
 @ cdecl _ismbckata(long)
-@ stub _ismbcl0(long)
+@ cdecl _ismbcl0(long)
 @ stub _ismbcl1(long)
 @ stub _ismbcl2(long)
 @ cdecl _ismbclegal(long)
diff --git a/dlls/msvcr71/msvcr71.spec b/dlls/msvcr71/msvcr71.spec
index f9c5afedca4..b7acbfbcfb3 100644
--- a/dlls/msvcr71/msvcr71.spec
+++ b/dlls/msvcr71/msvcr71.spec
@@ -376,7 +376,7 @@
 @ cdecl _ismbcgraph(long)
 @ cdecl _ismbchira(long)
 @ cdecl _ismbckata(long)
-@ stub _ismbcl0(long)
+@ cdecl _ismbcl0(long)
 @ stub _ismbcl1(long)
 @ stub _ismbcl2(long)
 @ cdecl _ismbclegal(long)
diff --git a/dlls/msvcr80/msvcr80.spec b/dlls/msvcr80/msvcr80.spec
index 5bfa4acbf4f..fdc0667f455 100644
--- a/dlls/msvcr80/msvcr80.spec
+++ b/dlls/msvcr80/msvcr80.spec
@@ -658,7 +658,7 @@
 @ stub _ismbchira_l
 @ cdecl _ismbckata(long)
 @ stub _ismbckata_l
-@ stub _ismbcl0(long)
+@ cdecl _ismbcl0(long)
 @ stub _ismbcl0_l
 @ stub _ismbcl1(long)
 @ stub _ismbcl1_l
diff --git a/dlls/msvcr90/msvcr90.spec b/dlls/msvcr90/msvcr90.spec
index e39fdee557b..cb8344cdc7d 100644
--- a/dlls/msvcr90/msvcr90.spec
+++ b/dlls/msvcr90/msvcr90.spec
@@ -636,7 +636,7 @@
 @ stub _ismbchira_l
 @ cdecl _ismbckata(long)
 @ stub _ismbckata_l
-@ stub _ismbcl0(long)
+@ cdecl _ismbcl0(long)
 @ stub _ismbcl0_l
 @ stub _ismbcl1(long)
 @ stub _ismbcl1_l
diff --git a/dlls/msvcrt/mbcs.c b/dlls/msvcrt/mbcs.c
index 49d66780b4e..63be8057285 100644
--- a/dlls/msvcrt/mbcs.c
+++ b/dlls/msvcrt/mbcs.c
@@ -2443,3 +2443,17 @@ unsigned int CDECL _mbctokata(unsigned int c)
         return (c - 0x829f) + 0x8340 + (c >= 0x82de ? 1 : 0);
     return c;
 }
+
+
+/*********************************************************************
+ *		_ismbcl0 (MSVCRT.@)
+ */
+int CDECL _ismbcl0(unsigned int c)
+{
+  if(get_mbcinfo()->mbcodepage == 932)
+  {
+    /* JIS non-Kanji */
+    return (c >= 0x8140 && c <= 0x889e);
+  }
+  return 0;
+}
diff --git a/dlls/msvcrt/msvcrt.spec b/dlls/msvcrt/msvcrt.spec
index c23c72b6559..ee59ae6aef9 100644
--- a/dlls/msvcrt/msvcrt.spec
+++ b/dlls/msvcrt/msvcrt.spec
@@ -604,7 +604,7 @@
 # stub _ismbchira_l(long ptr)
 @ cdecl _ismbckata(long)
 # stub _ismbckata_l(long ptr)
-@ stub _ismbcl0(long)
+@ cdecl _ismbcl0(long)
 # stub _ismbcl0_l(long ptr)
 @ stub _ismbcl1(long)
 # stub _ismbcl1_l(long ptr)
diff --git a/dlls/msvcrt/tests/string.c b/dlls/msvcrt/tests/string.c
index 04e20c16f77..1681001a86f 100644
--- a/dlls/msvcrt/tests/string.c
+++ b/dlls/msvcrt/tests/string.c
@@ -3193,6 +3193,29 @@ static void test__mbscmp(void)
     ok(ret == 1, "got %d\n", ret);
 }
 
+static void test__ismbclx(void)
+{
+    int cp, ret;
+
+    ret = _ismbcl0(0);
+    ok(!ret, "got %d\n", ret);
+
+    cp = _setmbcp(1252);
+
+    ret = _ismbcl0(0x8140);
+    ok(!ret, "got %d\n", ret);
+
+    _setmbcp(932);
+
+    ret = _ismbcl0(0);
+    ok(!ret, "got %d\n", ret);
+
+    ret = _ismbcl0(0x8140);
+    ok(ret, "got %d\n", ret);
+
+    _setmbcp(cp);
+}
+
 START_TEST(string)
 {
     char mem[100];
@@ -3308,4 +3331,5 @@ START_TEST(string)
     test__strnset_s();
     test__wcsset_s();
     test__mbscmp();
+    test__ismbclx();
 }
diff --git a/dlls/ucrtbase/ucrtbase.spec b/dlls/ucrtbase/ucrtbase.spec
index 7a07b719212..ce1e24e1ef3 100644
--- a/dlls/ucrtbase/ucrtbase.spec
+++ b/dlls/ucrtbase/ucrtbase.spec
@@ -476,7 +476,7 @@
 @ stub _ismbchira_l
 @ cdecl _ismbckata(long)
 @ stub _ismbckata_l
-@ stub _ismbcl0(long)
+@ cdecl _ismbcl0(long)
 @ stub _ismbcl0_l
 @ stub _ismbcl1(long)
 @ stub _ismbcl1_l