diff --git a/keymap_hhkb.c b/keymap_hhkb.c
index 11a3888f..7074df41 100644
--- a/keymap_hhkb.c
+++ b/keymap_hhkb.c
@@ -1,11 +1,14 @@
 /* 
  * keymap for modified macway keyboarq
  */
+#include <stdbool.h>
 #include <avr/pgmspace.h>
 #include "matrix.h"
 #include "keymap_hhkb.h"
+#include "usb_keyboard.h"
 
 int current_layer = 0;
+bool key_sent = false;
 
 /*
  * Layer0(Default Layer)
@@ -21,7 +24,7 @@ int current_layer = 0;
  *       |Gui|Alt  |Space                  |Fn3  |Gui|
  *       `-------------------------------------------'
  * 
- * Layer1(Fn1) HHKB mode
+ * Layer1(Fn) HHKB mode
  * ,-----------------------------------------------------------.
  * |Pow| F1| F2| F3| F4| F5| F6| F7| F8| F9|F10|F11|F12|Ins|Del|
  * |-----------------------------------------------------------|
@@ -34,34 +37,56 @@ int current_layer = 0;
  *      |Gui |Alt  |Space                  |Alt  |Gui|
  *      `--------------------------------------------'
  * 
- * Layer2(Fn2) mouse mode
+ * Layer3(RALT) vi mode
  * ,-----------------------------------------------------------.
- * |Esc|   |   |   |   |   |   |   |   |   |   |   |   |   |   |
+ * |Esc| F1| F2| F3| F4| F5| F6| F7| F8| F9|F10|F11|F12|Ins|Del|
  * |-----------------------------------------------------------|
- * |Tab  |   |   |   |   |   |   |   |   |   |   |   |   |Backs|
- * |-----------------------------------------------------------|
- * |Contro|   |   |   |   |   |   |   |MwL|MwD|MwU|MwR|Return  |
- * |-----------------------------------------------------------|
- * |Shift   |   |   |   |   |   |   |McL|McD|McU|McR|xxxxxx|   |
- * `-----------------------------------------------------------'
- *      |Gui |Alt  |Mb1                    |Mb1  |Mb2|
- *      `--------------------------------------------'
- * 
- * Layer3(Fn3) vi mode
- * ,-----------------------------------------------------------.
- * |Esc| F1| F2| F3| F4| F5| F6| F7| F8| F9|F10|F11|F12|   |   |
- * |-----------------------------------------------------------|
- * |Tab  |   |   |   |   |   |Hom|PgD|PgUlEnd|   |MwD|MwU|Backs|
+ * |Tab  |   |   |   |   |   |Hom|PgD|PgUlEnd|   |   |   |Backs|
  * |-----------------------------------------------------------|
  * |Contro|   |   |   |   |   |Lef|Dow|Up |Rig|   |   |Return  |
  * |-----------------------------------------------------------|
- * |Shift   |   |   |   |   |   |   |McL|McD|McU|McR|Mb1   |   |
+ * |Shift   |   |   |   |   |   |McL|McD|McU|McR|Mb1|Mb2   |   |
  * `-----------------------------------------------------------'
- *       |Gui|Alt  |Mb1                    |xxxxx|Mb2|
+ *       |Gui|Alt  |Sapce                  |xxxxx|Mb3|
  *       `-------------------------------------------'
+ *
+ * Layer4(semicolon) mouse mode
+ * ,-----------------------------------------------------------.
+ * |Esc|   |   |   |   |   |   |   |   |   |   |   |   |   |   |
+ * |-----------------------------------------------------------|
+ * |Tab  |   |   |   |   |   |MwL|MwD|MwU|MwR|   |   |   |Backs|
+ * |-----------------------------------------------------------|
+ * |Contro|   |   |   |   |   |McL|McD|McU|McR|xxx|   |Return  |
+ * |-----------------------------------------------------------|
+ * |Shift   |   |   |   |   |   |   |Mb1|Mb2|Mb3|   |Shift |   |
+ * `-----------------------------------------------------------'
+ *      |Gui |Alt  |Mb1                    |Alt  |Gui|
+ *      `--------------------------------------------'
+ * 
  * Mc: Mouse Cursor / Mb: Mouse Button / Mw: Mouse Wheel 
  */
+
+/* keycode sent when Fn key released without using layer keys. */
+static const uint8_t PROGMEM FnKey[] = {
+    KB_NO,          // this must be KB_NO. (not used)
+    KB_NO,          // FN_1
+    KB_RALT,        // FN_2
+    KB_SCOLON,      // FN_3
+};
+
 static const uint8_t PROGMEM Keymap[][MATRIX_ROWS][MATRIX_COLS] = {
+/*  plain keymap
+    {
+        { KB_2,       KB_Q,       KB_W,       KB_S,       KB_A,       KB_Z,       KB_X,       KB_C        },
+        { KB_3,       KB_4,       KB_R,       KB_E,       KB_D,       KB_F,       KB_V,       KB_B        },
+        { KB_5,       KB_6,       KB_Y,       KB_T,       KB_G,       KB_H,       KB_N,       KB_NO       },
+        { KB_1,       KB_ESCAPE,  KB_TAB,     KB_LCTRL,   KB_LSHIFT,  KB_LGUI,    KB_LALT,    KB_SPACE    },
+        { KB_7,       KB_8,       KB_U,       KB_I,       KB_K,       KB_J,       KB_M,       KB_NO       },
+        { KB_BSLASH,  KB_GRAVE,   KB_BSPACE,  KB_ENTER,   FN_1,       KB_RSHIFT,  KB_RGUI,    KB_RALT     },
+        { KB_9,       KB_0,       KB_O,       KB_P,       KB_SCOLON,  KB_L,       KB_COMMA,   KB_NO       },
+        { KB_MINUS,   KB_EQUAL,   KB_RBRACKET,KB_LBRACKET,KB_QUOTE,   KB_SLASH,   KB_DOT,     KB_NO       },
+    },
+*/
     // 0: default
     {
         { KB_2,       KB_Q,       KB_W,       KB_S,       KB_A,       KB_Z,       KB_X,       KB_C        },
@@ -69,11 +94,11 @@ static const uint8_t PROGMEM Keymap[][MATRIX_ROWS][MATRIX_COLS] = {
         { KB_5,       KB_6,       KB_Y,       KB_T,       KB_G,       KB_H,       KB_N,       KB_NO       },
         { KB_1,       KB_ESCAPE,  KB_TAB,     KB_LCTRL,   KB_LSHIFT,  KB_LGUI,    KB_LALT,    KB_SPACE    },
         { KB_7,       KB_8,       KB_U,       KB_I,       KB_K,       KB_J,       KB_M,       KB_NO       },
-        { KB_BSLASH,  KB_GRAVE,   KB_BSPACE,  FN_4,       FN_1,       FN_2,       KB_RGUI,    FN_3        },
-        { KB_9,       KB_0,       KB_O,       KB_P,       KB_SCOLON,  KB_L,       KB_COMMA,   KB_NO       },
+        { KB_BSLASH,  KB_GRAVE,   KB_BSPACE,  KB_ENTER,   FN_1,       KB_RSHIFT,  KB_RGUI,    FN_2        },
+        { KB_9,       KB_0,       KB_O,       KB_P,       FN_3,       KB_L,       KB_COMMA,   KB_NO       },
         { KB_MINUS,   KB_EQUAL,   KB_RBRACKET,KB_LBRACKET,KB_QUOTE,   KB_SLASH,   KB_DOT,     KB_NO       },
     },
-    // 1: FN_1(HHKB Fn) HHKB mode
+    // 1: FN_1 HHKB mode(Fn)
     {
         { KB_F2,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO       },
         { KB_F3,      KB_F4,      KB_NO,      KB_NO,      KB_MUTE,    KB_F20,     KB_NO,      KB_NO       },
@@ -84,38 +109,27 @@ static const uint8_t PROGMEM Keymap[][MATRIX_ROWS][MATRIX_COLS] = {
         { KB_F9,      KB_F10,     KB_SCKLOCK, KB_BREAK,   KB_LEFT,    KB_PGUP,    KB_END,     KB_NO       },
         { KB_F11,     KB_F12,     KB_NO,      KB_UP,      KB_RIGHT,   KB_DOWN,    KB_PGDOWN,  KB_NO       },
     },
-    // 2: FN_2(Right Shift) mouse mode
-    {
-        { KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO       },
-        { KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO       },
-        { KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO       },
-        { KB_NO,      KB_ESCAPE,  KB_TAB,     KB_LCTRL,   KB_LSHIFT,  KB_LGUI,    KB_LALT,    MS_BTN1     },
-        { KB_NO,      KB_NO,      KB_NO,      KB_NO,      MS_WH_LEFT, KB_NO,      MS_LEFT,    KB_NO       },
-        { KB_NO,      KB_NO,      KB_BSPACE,  KB_ENTER,   KB_NO,      KB_NO,      MS_BTN2,    MS_BTN1     },
-        { KB_NO,      KB_NO,      KB_NO,      KB_NO,      MS_WH_UP,   MS_WH_DOWN, MS_DOWN,    KB_NO       },
-        { KB_NO,      KB_NO,      KB_NO,      KB_NO,      MS_WH_RIGHT,MS_RIGHT,   MS_UP,      KB_NO       },
-    },
-    // 3: FN_3(Right Alt) vi mode
+    // 2: FN_2 vi mode(RALT)
     {
         { KB_F2,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO       },
-        { KB_F3,      KB_F4,      KB_NO,      KB_NO,      KB_NO,      KB_F20,     KB_NO,      KB_NO       },
-        { KB_F5,      KB_F6,      KB_HOME,    KB_NO,      KB_NO,      KB_LEFT,    KB_NO,      KB_NO       },
-        { KB_F1,      KB_ESCAPE,  KB_TAB,     KB_LCTRL,   KB_LSHIFT,  KB_LGUI,    KB_LALT,    MS_BTN1     },
-        { KB_F7,      KB_F8,      KB_PGDOWN,  KB_PGUP,    KB_UP,      KB_DOWN,    MS_LEFT,    KB_NO       },
-        { KB_INSERT,  KB_NO,      KB_BSPACE,  KB_ENTER,   KB_NO,      MS_BTN1,    MS_BTN2,    KB_NO       },
-        { KB_F9,      KB_F10,     KB_END,     KB_NO,      KB_NO,      KB_RIGHT,   MS_DOWN,    KB_NO       },
-        { KB_F11,     KB_F12,     MS_WH_UP,   MS_WH_DOWN, KB_NO,      MS_RIGHT,   MS_UP,      KB_NO       },
+        { KB_F3,      KB_F4,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO       },
+        { KB_F5,      KB_F6,      KB_HOME,    KB_NO,      KB_NO,      KB_LEFT,    MS_LEFT,    KB_NO       },
+        { KB_F1,      KB_ESCAPE,  KB_TAB,     KB_LCTRL,   KB_LSHIFT,  KB_LGUI,    KB_LALT,    KB_SPACE    },
+        { KB_F7,      KB_F8,      KB_PGDOWN,  KB_PGUP,    KB_UP,      KB_DOWN,    MS_DOWN,    KB_NO       },
+        { KB_INSERT,  KB_DELETE,  KB_BSPACE,  KB_ENTER,   KB_NO,      MS_BTN2,    MS_BTN3,    KB_NO       },
+        { KB_F9,      KB_F10,     KB_END,     KB_NO,      KB_NO,      KB_RIGHT,   MS_UP,      KB_NO       },
+        { KB_F11,     KB_F12,     MS_WH_UP,   MS_WH_DOWN, KB_NO,      MS_BTN1,    MS_RIGHT,   KB_NO       },
     },
-    // 3: FN_4(Enter) vi mouse mode
+    // 3: FN_3 vi mouse mode(SCOLON)
     {
-        { KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO       },
-        { KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO       },
-        { KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO       },
-        { KB_NO,      KB_ESCAPE,  KB_TAB,     KB_LCTRL,   KB_LSHIFT,  KB_LGUI,    KB_LALT,    MS_BTN1     },
-        { KB_NO,      KB_NO,      KB_NO,      KB_NO,      MS_LEFT,    KB_NO,      KB_NO,      KB_NO       },
-        { KB_NO,      KB_NO,      KB_BSPACE,  KB_NO,      KB_NO,      KB_NO,      MS_BTN2,    MS_BTN1     },
-        { KB_NO,      KB_NO,      KB_NO,      KB_NO,      MS_UP,      MS_DOWN,    KB_NO,      KB_NO       },
-        { KB_NO,      KB_NO,      KB_NO,      KB_NO,      MS_RIGHT,   KB_NO,      KB_NO,      KB_NO       },
+        { KB_F2,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO       },
+        { KB_F3,      KB_F4,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO,      KB_NO       },
+        { KB_F5,      KB_F6,      MS_WH_LEFT, KB_NO,      KB_NO,      MS_LEFT,    KB_NO,      KB_NO       },
+        { KB_F1,      KB_ESCAPE,  KB_TAB,     KB_LCTRL,   KB_LSHIFT,  KB_LGUI,    KB_LALT,    MS_BTN1     },
+        { KB_F7,      KB_F8,      MS_WH_DOWN, MS_WH_UP,   MS_UP,      MS_DOWN,    MS_BTN1,    KB_NO       },
+        { KB_NO,      KB_NO,      KB_BSPACE,  KB_ENTER,   KB_NO,      KB_RSHIFT,  KB_RGUI,    KB_RALT     },
+        { KB_F9,      KB_F10,     MS_WH_RIGHT,KB_NO,      KB_NO,      MS_RIGHT,   MS_BTN2,    KB_NO       },
+        { KB_F11,     KB_F12,     KB_NO,      KB_NO,      KB_NO,      KB_NO,      MS_BTN3,    KB_NO       },
     },
 };
 
@@ -130,21 +144,46 @@ uint8_t get_keycode(int layer, int row, int col)
 }
 
 int get_layer(void) {
+    // keep modifier state when Fn key pressed
+    static uint8_t preserved_modifiers = 0;
     int layer = 0;
+    uint8_t modifiers = 0;
     for (int row = 0; row < MATRIX_ROWS; row++) {
         for (int col = 0; col < MATRIX_ROWS; col++) {
-            if (matrix[row] & 1<<col) continue;
-            if (get_keycode(0, row, col) == FN_1) layer = 1;
-            if (get_keycode(0, row, col) == FN_2) layer = 2;
-            if (get_keycode(0, row, col) == FN_3) layer = 3;
-            if (get_keycode(0, row, col) == FN_4) layer = 4;
+            if (matrix[row] & 1<<col) continue; // NOT pressed
+            uint8_t code = get_keycode(0, row, col);
+            if      (code == FN_1) layer = 1;
+            else if (code == FN_2) layer = 2;
+            else if (code == FN_3) layer = 3;
+            else if (code == FN_4) layer = 4;
+            else if (KB_LCTRL <= code && code <= KB_RGUI)
+                modifiers |= 1<<(code & 0x07);
         }
     }
 
-    if (layer == 0)
-        current_layer = 0;
-    else if (current_layer == 0)
+    // TODO: this logic should go anywhere
+    // TODO: need timeout for key_sent
+    // send key when Fn key reloeased without used
+    if (layer != current_layer) {
+        if (layer == 0 && !key_sent) {
+            uint8_t code = pgm_read_byte(&FnKey[current_layer]);
+            if (code) {
+                // send modifiers when Fn key pressed.
+                keyboard_modifier_keys = preserved_modifiers;
+                for (int i = 0; i < 6; i++) keyboard_keys[i] = KB_NO;
+
+                if (KB_LCTRL <= code && code <= KB_RGUI) {
+                    keyboard_modifier_keys |= 1<<(code & 0x07);
+                } else  {
+                    keyboard_keys[0] = code;
+                }
+                usb_keyboard_send();
+            }
+        }
         current_layer = layer;
+        key_sent = false;
+        preserved_modifiers = modifiers;
+    }
 
     return current_layer;
 }
diff --git a/keymap_hhkb.h b/keymap_hhkb.h
index d2af65e9..1c2d100e 100644
--- a/keymap_hhkb.h
+++ b/keymap_hhkb.h
@@ -4,10 +4,16 @@
 #include <stdint.h>
 #include "usb_keycodes.h"
 
-int get_layer(void);
-uint8_t get_keycode(int layer, int row, int col);
 
 #define MATRIX_ROWS 8
 #define MATRIX_COLS 8
 
+
+extern int current_layer;
+extern bool key_sent;
+
+
+int get_layer(void);
+uint8_t get_keycode(int layer, int row, int col);
+
 #endif
diff --git a/tmk.c b/tmk.c
index b02efedd..7c678a7e 100644
--- a/tmk.c
+++ b/tmk.c
@@ -176,6 +176,7 @@ int main(void)
             if (mouse_x || mouse_y || mouse_wheel || mouse_hwheel || mouse_btn != mouse_buttons) {
                 mouse_buttons = mouse_btn;
                 usb_mouse_move(mouse_x, mouse_y, mouse_wheel, mouse_hwheel);
+                key_sent = true;
 
                 // acceleration
                 _delay_ms(MOUSE_DELAY_MS >> (mouse_repeat < MOUSE_DELAY_ACC ? mouse_repeat : MOUSE_DELAY_ACC));
@@ -191,6 +192,8 @@ int main(void)
                     //Rollover
                 }
                 usb_keyboard_send();
+                if (keyboard_keys[0])
+                    key_sent = true;
 
                 // LED flash for debug
                 LED_CONFIG;