diff --git a/map/kata.map b/map/kata.map
index d7d2de3..5b2ea62 100644
--- a/map/kata.map
+++ b/map/kata.map
@@ -33,7 +33,6 @@ sho	ショ
 syo	ショ
 ja	ジャ
 ju	ジュ
-je	ジェ
 jo	ジョ
 su	ス
 zu	ズ
@@ -119,6 +118,7 @@ xn	ン
 v	ヴ
 xa	ァ
 xi	ィ
+xu	ゥ
 xe	ェ
 xo	ォ
 cc	ッ
@@ -128,7 +128,6 @@ pp	ッ
 tt	ッ
 tch	ッ
 ss	ッ
-xn	ン
 di	ディ
 fa	ファ
 fi	フィ
@@ -136,6 +135,7 @@ fe	フェ
 fo	フォ
 va	ヴァ
 vi	ヴィ
+vu	ヴ
 ve	ヴェ
 vo	ヴォ
 .	。
diff --git a/strans.c b/strans.c
index 353eacc..a137409 100644
--- a/strans.c
+++ b/strans.c
@@ -27,7 +27,7 @@ backmap(Im *im)
 Lang langs[] = {
 	{LangEN,    "english", nil,      transmap, backmap, dictqmap, nil, nil},
 	{LangJP,    "hira",    "kanji",  transmap, backjp,  dictqjp,  nil, nil},
-	{LangJPK,   "kata",    "kanji",  transmap, backjp,  dictqjp,  nil, nil},
+	{LangJPK,   "kata",    nil,      transmap, backjp,  dictqjp,  nil, nil},
 	{LangKO,    "hangul",  nil,      transko,  backko,  dictqmap, nil, nil},
 	{LangEMOJI, nil,       "emoji",  nil,      nil,     nil,      nil, nil},
 	{LangVI,    "telex",   nil,      transvi,  backvi,  dictqmap, nil, nil},
@@ -213,6 +213,23 @@ backjp(Im *im)
 		spopr(&im->pre);
 }
 
+static int
+issmalltsu(Str *s)
+{
+	return s->n == 1 && (s->r[0] == L'っ' || s->r[0] == L'ッ');
+}
+
+static void
+keeptail(Str *s)
+{
+	int i;
+
+	for(i = 1; i < s->n; i++)
+		s->r[i-1] = s->r[i];
+	if(s->n > 0)
+		s->n--;
+}
+
 static int
 dotransjp(Rune c, Str *com)
 {
@@ -228,8 +245,13 @@ dotransjp(Rune c, Str *com)
 	key = im.raw;
 	if(key.n < Maxrunes)
 		sputr(&key, c);
+	sclear(&mapped);
 	if(maplookup(im.l->map, &key, &mapped)){
 		im.raw = key;
+		if(issmalltsu(&mapped)){
+			sappend(&im.pre, &mapped);
+			keeptail(&im.raw);
+		}
 		dictqjp(&im);
 		return 1;
 	}
diff --git a/tests/engine_test.c b/tests/engine_test.c
index b7da9d4..e75306b 100644
--- a/tests/engine_test.c
+++ b/tests/engine_test.c
@@ -481,6 +481,41 @@ engine_japanese_backspace_and_boundaries(struct ct *t)
 	}
 }
 
+void
+engine_katakana_sequences(struct ct *t)
+{
+	static const struct {
+		char *keys;
+		char *want;
+	} cases[] = {
+		{ "kitte", "キッテ" },
+		{ "katta", "カッタ" },
+		{ "gakkou", "ガッコウ" },
+		{ "matcha", "マッチャ" },
+		{ "xu", "ゥ" },
+		{ "vu", "ヴ" },
+	};
+	Dictreq req;
+	Str com, shown;
+	int i;
+
+	newestrequest(&req);
+	for(i = 0; i < nelem(cases); i++){
+		init();
+		im.l = getlang(LangJPK);
+		sclear(&com);
+		if(!typekeys(t, cases[i].keys, &com))
+			continue;
+		checkstr(t, cases[i].keys, "", &com);
+		shown = shownpre(&im);
+		checkstr(t, cases[i].keys, cases[i].want, &shown);
+		CT_CHECK(t, keystroke(Kret, 0, &com));
+		checkstr(t, "committed Katakana", cases[i].want, &com);
+	}
+	CT_EQ_INT(t, 0, newestrequest(&req));
+	CT_EQ_PTR(t, nil, getlang(LangJPK)->dictname);
+}
+
 void
 engine_emoji_single_candidate(struct ct *t)
 {
diff --git a/tests/test.h b/tests/test.h
index f944a01..00832f5 100644
--- a/tests/test.h
+++ b/tests/test.h
@@ -36,6 +36,7 @@ void	engine_telex_history_bound(struct ct*);
 void	engine_japanese_readings(struct ct*);
 void	engine_japanese_candidates(struct ct*);
 void	engine_japanese_backspace_and_boundaries(struct ct*);
+void	engine_katakana_sequences(struct ct*);
 void	engine_emoji_single_candidate(struct ct*);
 void	engine_emoji_queries(struct ct*);
 void	engine_emoji_digit_aliases(struct ct*);
diff --git a/tests/unit_test.c b/tests/unit_test.c
index 62e3654..97662db 100644
--- a/tests/unit_test.c
+++ b/tests/unit_test.c
@@ -85,6 +85,7 @@ static const struct ct_test tests[] = {
 	{ "engine/japanese-readings", engine_japanese_readings },
 	{ "engine/japanese-candidates", engine_japanese_candidates },
 	{ "engine/japanese-backspace-boundaries", engine_japanese_backspace_and_boundaries },
+	{ "engine/katakana-sequences", engine_katakana_sequences },
 	{ "engine/emoji-single-candidate", engine_emoji_single_candidate },
 	{ "engine/emoji-queries", engine_emoji_queries },
 	{ "engine/emoji-digit-aliases", engine_emoji_digit_aliases },