diff --git a/src/boards/bj56.c b/src/boards/bj56.c
new file mode 100644
index 0000000..a73a2ce
--- /dev/null
+++ b/src/boards/bj56.c
@@ -0,0 +1,119 @@
+/* FCEUmm - NES/Famicom Emulator
+ *
+ * Copyright notice for this file:
+ *  Copyright (C) 2019 Libretro Team
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/* NES 2.0 Mapper 526 is used for a bootleg version of Namco's 三国志: 中原の覇者 (Sangokushi: Chūgen no Hasha).
+ * Its UNIF board name is UNL-BJ-56.
+ * Mirroring seems to be hard-wired (to vertical).
+ * https://wiki.nesdev.com/w/index.php/NES_2.0_Mapper_526
+ */
+
+#include "mapinc.h"
+
+static uint8 preg[4], creg[8];
+static uint32 IRQCount;
+static uint8 *WRAM = NULL;
+static uint32 WRAMSIZE;
+
+static SFORMAT StateRegs[] =
+{
+	{ preg, 4, "PREG" },
+	{ creg, 8, "CREG" },
+	{ &IRQCount, 4, "IRQC" },
+	{ 0 }
+};
+
+static void Sync(void) {
+	uint8 i;
+	setprg8r(0x10, 0x6000, 0);
+	setprg8(0x8000, preg[0]);
+	setprg8(0xA000, preg[1]);
+	setprg8(0xC000, preg[2]);
+	setprg8(0xE000, preg[3]);
+	for (i = 0; i < 8; i++)
+		setchr1((i << 10), creg[i]);
+	setmirror(MI_V);
+}
+
+static DECLFW(UNLBJ56Write) {
+/*	FCEU_printf("Wr: A:%04x V:%02x\n", A, V); */
+	A &= 0xF00F;
+	if (A <= 0x8007) {
+		creg[A & 0x07] = V;
+		Sync();
+	} else if (A <= 0x800B) {
+		preg[A & 0x03] = V;
+		Sync();
+	} else {
+		switch (A & 0x0F) {
+		case 0x0D:
+		case 0x0F:
+			/* One of these two acknowledges a pending IRQ, and the other
+			 * resets to IRQ counter to zero. Because they are always written
+			 * to one after the other, it's not clear which one does which. */
+			X6502_IRQEnd(FCEU_IQEXT);
+			IRQCount = 0;
+			break;
+		}
+	}
+}
+
+static void FP_FASTAPASS(1) UNLBJ56IRQHook(int a) {
+	IRQCount += a;
+	if (IRQCount & 4096)
+		X6502_IRQBegin(FCEU_IQEXT);
+}
+
+static void UNLBJ56Close(void) {
+	if (WRAM)
+		FCEU_gfree(WRAM);
+	WRAM = NULL;
+}
+
+static void UNLBJ56Power(void) {
+	preg[0] = ~3;
+	preg[1] = ~2;
+	preg[2] = ~1;
+	preg[3] = ~0;
+	Sync();
+	SetReadHandler(0x6000, 0xFFFF, CartBR);
+	SetWriteHandler(0x6000, 0x7FFF, CartBW);
+	SetWriteHandler(0x8000, 0x800F, UNLBJ56Write);
+	FCEU_CheatAddRAM(WRAMSIZE >> 10, 0x6000, WRAM);
+}
+
+static void StateRestore(int version) {
+	Sync();
+}
+
+void UNLBJ56_Init(CartInfo *info) {
+	info->Power = UNLBJ56Power;
+	info->Close = UNLBJ56Close;
+	MapIRQHook = UNLBJ56IRQHook;
+	GameStateRestore = StateRestore;
+	WRAMSIZE = 8192;
+	WRAM = (uint8*)FCEU_gmalloc(WRAMSIZE);
+	SetupCartPRGMapping(0x10, WRAM, WRAMSIZE, 1);
+	if (info->battery) {
+		info->SaveGame[0] = WRAM;
+		info->SaveGameLen[0] = WRAMSIZE;
+	}
+	AddExState(WRAM, WRAMSIZE, 0, "WRAM");
+	AddExState(&StateRegs, ~0, 0, 0);
+}
diff --git a/src/unif.c b/src/unif.c
index 3e482e7..c2f4b89 100644
--- a/src/unif.c
+++ b/src/unif.c
@@ -496,6 +496,8 @@ static BMAPPING bmap[] = {
 	{ "JC-016-2", Mapper205_Init, 0 },
 	{ "AX-40G", UNLAX40G_Init, 0 },
 	{ " BMC-STREETFIGTER-GAME4IN1", BMCSFGAME4IN1_Init, 0 },
+	{ "G631", BMCGhostbusters63in1_Init, 0 },
+	{ "BJ-56", UNLBJ56_Init, 0 },
 
 #ifdef COPYFAMI
 	{ "COPYFAMI_MMC3", MapperCopyFamiMMC3_Init, 0 },
diff --git a/src/unif.h b/src/unif.h
index 9bcf745..d2111b3 100644
--- a/src/unif.h
+++ b/src/unif.h
@@ -182,6 +182,7 @@ void BTL900218_Init(CartInfo *info);		/* m524 */
 void UNLAX40G_Init(CartInfo *info);			/* m527 */
 void BMCK3088_Init(CartInfo *info);			/* m287 */
 void BMCSFGAME4IN1_Init(CartInfo *info);	/* m049 */
+void UNLBJ56_Init(CartInfo *info);			/* m526 */
 
 #ifdef COPYFAMI
 void MapperCopyFamiMMC3_Init(CartInfo *info);