diff --git a/mjcore/data/confitem.csv b/mjcore/data/confitem.csv
index f0996859..4bc491f9 100644
--- a/mjcore/data/confitem.csv
+++ b/mjcore/data/confitem.csv
@@ -110,7 +110,7 @@
 126,16,0,,,,,,red_four,赤四,赤ドラ(４の牌)の有無を設定します,no,circle_suit,>>>,>>>,character_suit,character_circle_suit,,,,,,,,,,,,,,
 127,9,0,,,,,,red_five,赤五,赤ドラの有無を設定します,3tiles,4tiles,6tiles,2_circle_tiles,>>>,>>>,>>>,>>>,no,circle_suit,bamboo_suit,circle_bamboo_suit,character_suit,character_circle_suit,character_bamboo_suit,,,,,
 127,6,0,,,,,,red_five,赤五,赤ドラの有無を設定します,2tiles,>>>,4tiles,2_circle_tiles,>>>,>>>,>>>,>>>,no,circle_suit,bamboo_suit,,,,,,,,,
-127,16,0,,,,,,red_five,赤五,赤ドラの有無を設定します,2tiles,>>>,4tiles,2_circle_tiles,>>>,>>>,>>>,>>>,no,circle_suit,bamboo_suit,,,,,,,,,
+127,16,0,,,,,,red_five,赤五,赤ドラの有無を設定します,2tiles,>>>,4tiles,2_circle_tiles,>>>,>>>,>>>,>>>,no,circle_suit,>>>,>>>,character_suit,,,,,,,
 128,9,0,,,,,,red_six,赤六,赤ドラ(６の牌)の有無を設定します,no,circle_suit,bamboo_suit,circle_bamboo_suit,character_suit,character_circle_suit,character_bamboo_suit,all_three_suits,,,,,,,,,,,,
 128,6,0,,,,,,red_six,赤六,赤ドラ(６の牌)の有無を設定します,no,circle_suit,bamboo_suit,circle_bamboo_suit,,,,,,,,,,,,,,,,
 128,16,0,,,,,,red_six,赤六,赤ドラ(６の牌)の有無を設定します,no,circle_suit,>>>,>>>,character_suit,character_circle_suit,,,,,,,,,,,,,,
diff --git a/mjcore/prepare.cpp b/mjcore/prepare.cpp
index 123f341a..f1f8a7b5 100644
--- a/mjcore/prepare.cpp
+++ b/mjcore/prepare.cpp
@@ -92,7 +92,20 @@ inline void redtiles(GameTable* const gameStat, UInt8ByTile& tilepos) { // 赤
 		}
 	}
 	// 5のドラは特殊
-	if (gameStat->chkGameType(SanmaX)) { // 三麻
+	if (gameStat->chkGameType(SanmaSeto)) { // 瀬戸内三麻
+		if (RuleData::chkRule("red_five", "2tiles")) {
+			gameStat->Deck[tilepos[CircleFive]].red = AkaDora;
+			gameStat->Deck[tilepos[CharacterFive]].red = AkaDora;
+		} else if (RuleData::chkRule("red_five", "4tiles")) {
+			gameStat->Deck[tilepos[CircleFive]].red = AkaDora;
+			gameStat->Deck[tilepos[CircleFive] + 1].red = AkaDora;
+			gameStat->Deck[tilepos[CharacterFive]].red = AkaDora;
+			gameStat->Deck[tilepos[CharacterFive] + 1].red = AkaDora;
+		} else if (RuleData::chkRule("red_five", "2_circle_tiles")) {
+			gameStat->Deck[tilepos[CircleFive]].red = AkaDora;
+			gameStat->Deck[tilepos[CircleFive] + 1].red = AkaDora;
+		}
+	} else if (gameStat->chkGameType(SanmaX)) { // 三麻
 		if (RuleData::chkRule("red_five", "2tiles")) {
 			gameStat->Deck[tilepos[CircleFive]].red = AkaDora;
 			gameStat->Deck[tilepos[BambooFive]].red = AkaDora;