diff --git a/engine/engine.py b/engine/engine.py
index 1978dff..9b5bfa8 100644
--- a/engine/engine.py
+++ b/engine/engine.py
@@ -2051,6 +2051,16 @@ def __cmd_expand_segment(self, keyval, state):
             self.__shrink_segment(1)
             return True
 
+    def __move_cursor_char_length(self, length):
+        if self.__input_mode == INPUT_MODE_HIRAGANA:
+            self.__preedit_ja_string.move_cursor_hiragana_length(length)
+        elif self.__input_mode == INPUT_MODE_KATAKANA:
+            self.__preedit_ja_string.move_cursor_katakana_length(length)
+        elif self.__input_mode == INPUT_MODE_HALF_WIDTH_KATAKANA:
+            self.__preedit_ja_string.move_cursor_half_with_katakana_length(length)
+        else:
+            self.__preedit_ja_string.move_cursor(length)
+
     def __commit_nth_segment(self, commit_index, keyval, state):
 
         if commit_index >= len(self.__segments):
@@ -2066,10 +2076,10 @@ def __commit_nth_segment(self, commit_index, keyval, state):
             for i in xrange(0, commit_index + 1):
                 buf = self.__context.get_segment(i, NTH_UNCONVERTED_CANDIDATE)
                 commit_length += len(unicode(buf, "utf-8"))
-            self.__preedit_ja_string.move_cursor(commit_length - cursor)
+            self.__move_cursor_char_length(commit_length - cursor)
             for i in xrange(0, commit_length):
                 self.__preedit_ja_string.remove_before()
-            self.__preedit_ja_string.move_cursor(cursor - commit_length)
+            self.__move_cursor_char_length(cursor - commit_length)
 
             del self.__segments[0:commit_index + 1]
 
@@ -2080,7 +2090,7 @@ def __commit_nth_segment(self, commit_index, keyval, state):
                 self.__cursor_pos -= (commit_index + 1)
             else:
                 self.__cursor_pos = 0
-            (seg_index, text) = self.__segments[self.__cursor_pos]
+            text, cursor = self.__get_preedit()
             self.__convert_chars = text
             self.__context.set_string(text.encode ("utf-8"))
 
diff --git a/engine/jastring.py b/engine/jastring.py
index 78c281d..2ea6e3f 100644
--- a/engine/jastring.py
+++ b/engine/jastring.py
@@ -132,6 +132,77 @@ def move_cursor(self, delta):
         elif self.__cursor > len(self.__segments):
             self.__cursor = len(self.__segments)
 
+    # hiragana segments are not char lengths.
+    # e.g. 'ya' is 1 segment and 1 char and 'kya' is 1 segment and 2 chars.
+    def move_cursor_hiragana_length(self, length):
+        delta = length
+        if delta < 0:
+            if self.__cursor >= len(self.__segments):
+                delta = delta + (self.__cursor - len(self.__segments) + 1)
+                self.__cursor = len(self.__segments) - 1
+            while delta < 0:
+                text = unicode(self.__segments[self.__cursor].to_hiragana())
+                if len(text) > -delta:
+                    break
+                delta = delta + len(text)
+                self.__cursor = self.__cursor - 1
+        else:
+            if self.__cursor >= len(self.__segments):
+                self.__cursor = len(self.__segments)
+                return
+            while delta > 0:
+                text = unicode(self.__segments[self.__cursor].to_hiragana())
+                if len(text) > delta:
+                    break
+                delta = delta - len(text)
+                self.__cursor = self.__cursor + 1
+
+    def move_cursor_katakana_length(self, length):
+        delta = length
+        if delta < 0:
+            if self.__cursor >= len(self.__segments):
+                delta = delta + (self.__cursor - len(self.__segments) + 1)
+                self.__cursor = len(self.__segments) - 1
+            while delta < 0:
+                text = unicode(self.__segments[self.__cursor].to_katanaka())
+                if len(text) > -delta:
+                    break
+                delta = delta + len(text)
+                self.__cursor = self.__cursor - 1
+        else:
+            if self.__cursor >= len(self.__segments):
+                self.__cursor = len(self.__segments)
+                return
+            while delta > 0:
+                text = unicode(self.__segments[self.__cursor].to_katanaka())
+                if len(text) > delta:
+                    break
+                delta = delta - len(text)
+                self.__cursor = self.__cursor + 1
+
+    def move_cursor_half_with_katakana_length(self, length):
+        delta = length
+        if delta < 0:
+            if self.__cursor >= len(self.__segments):
+                delta = delta + (self.__cursor - len(self.__segments) + 1)
+                self.__cursor = len(self.__segments) - 1
+            while delta < 0:
+                text = unicode(self.__segments[self.__cursor].to_half_width_katakana())
+                if len(text) > -delta:
+                    break
+                delta = delta + len(text)
+                self.__cursor = self.__cursor - 1
+        else:
+            if self.__cursor >= len(self.__segments):
+                self.__cursor = len(self.__segments)
+                return
+            while delta > 0:
+                text = unicode(self.__segments[self.__cursor].to_half_width_katakana())
+                if len(text) > delta:
+                    break
+                delta = delta - len(text)
+                self.__cursor = self.__cursor + 1
+
     def _chk_text(self, s):
         period = self._prefs.get_value('common', 'period_style')
         symbol = self._prefs.get_value('common', 'symbol_style')