diff --git a/BizHawk.Emulation/BizHawk.Emulation.csproj b/BizHawk.Emulation/BizHawk.Emulation.csproj
index 0581efb55b..cc04200b3e 100644
--- a/BizHawk.Emulation/BizHawk.Emulation.csproj
+++ b/BizHawk.Emulation/BizHawk.Emulation.csproj
@@ -91,6 +91,7 @@
       <SubType>Code</SubType>
     </Compile>
     <Compile Include="Consoles\Nintendo\NES\Boards\Sunsoft1.cs" />
+    <Compile Include="Consoles\Nintendo\NES\Boards\Sunsoft4.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\SxROM.cs">
       <SubType>Code</SubType>
     </Compile>
diff --git a/BizHawk.Emulation/Consoles/Nintendo/NES/BoardSystem.cs b/BizHawk.Emulation/Consoles/Nintendo/NES/BoardSystem.cs
index ecd97ea62f..59b0ebb516 100644
--- a/BizHawk.Emulation/Consoles/Nintendo/NES/BoardSystem.cs
+++ b/BizHawk.Emulation/Consoles/Nintendo/NES/BoardSystem.cs
@@ -100,7 +100,7 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 				}
 			}
 
-			int ApplyMirroring(int addr)
+			protected int ApplyMirroring(int addr)
 			{
 				int block = (addr >> 10) & 3;
 				block = mirroring[block];
diff --git a/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/Sunsoft4.cs b/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/Sunsoft4.cs
new file mode 100644
index 0000000000..69a1dcf406
--- /dev/null
+++ b/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/Sunsoft4.cs
@@ -0,0 +1,125 @@
+using System;
+using System.IO;
+using System.Diagnostics;
+
+namespace BizHawk.Emulation.Consoles.Nintendo
+{
+	//AKA mapper 068
+
+	//After Burner 2
+	//Maharaja
+
+	class Sunsoft4 : NES.NESBoardBase
+	{
+		//configuration
+		int prg_bank_mask, chr_bank_mask, nt_bank_mask;
+
+		//state
+		ByteBuffer chr_regs_2k = new ByteBuffer(4);
+		ByteBuffer nt_regs = new ByteBuffer(2);
+		ByteBuffer prg_regs_16k = new ByteBuffer(2);
+		bool flag_m, flag_r;
+
+		public override void Dispose()
+		{
+			base.Dispose();
+			chr_regs_2k.Dispose();
+			nt_regs.Dispose();
+			prg_regs_16k.Dispose();
+		}
+
+		public override bool Configure(NES.EDetectionOrigin origin)
+		{
+			//configure
+			switch (Cart.board_type)
+			{
+				case "SUNSOFT-4":
+					AssertPrg(128); AssertChr(128,256); AssertVram(0); AssertWram(8); 
+					break;
+				default:
+					return false;
+			}
+
+			SetMirrorType(EMirrorType.Vertical);
+			prg_regs_16k[1] = 0xFF;
+			prg_bank_mask = Cart.prg_size / 16 - 1;
+			chr_bank_mask = Cart.chr_size / 2 - 1;
+			nt_bank_mask = Cart.chr_size - 1;
+			return true;
+		}
+
+		public override byte ReadPRG(int addr)
+		{
+			int bank_16k = addr >> 14;
+			int ofs = addr & ((1 << 14) - 1);
+			bank_16k = prg_regs_16k[bank_16k];
+			bank_16k &= prg_bank_mask;
+			addr = (bank_16k << 14) | ofs;
+			return ROM[addr];
+		}
+
+		public override byte ReadPPU(int addr)
+		{
+			if (addr < 0x2000)
+			{
+				//chr comes from normal chr mapping
+				int bank_2k = addr >> 11;
+				int ofs = addr & ((1 << 11) - 1);
+				bank_2k = chr_regs_2k[bank_2k];
+				bank_2k &= chr_bank_mask;
+				addr = (bank_2k << 11) | ofs;
+				return VROM[addr];
+			}
+			else
+			{
+				//nametable may come from "NT-ROM"
+				//which means from extra CHR data starting at bank 0x80
+				if (flag_r)
+				{
+					addr = ApplyMirroring(addr);
+					int bank_1k = (addr >> 10) & 3;
+					int ofs = addr & ((1 << 10) - 1);
+					bank_1k = nt_regs[bank_1k] + 0x80;
+					bank_1k &= nt_bank_mask;
+					addr = (bank_1k << 10) | ofs;
+					return VROM[addr];
+				}
+				else return base.ReadPPU(addr);
+			}
+		}
+
+		public override void WritePRG(int addr, byte value)
+		{
+			switch (addr & 0xF000)
+			{
+				case 0x0000: //$8000
+					chr_regs_2k[0] = value;
+					break;
+				case 0x1000: //$9000
+					chr_regs_2k[1] = value;
+					break;
+				case 0x2000: //$A000
+					chr_regs_2k[2] = value;
+					break;
+				case 0x3000: //$B000
+					chr_regs_2k[3] = value;
+					break;
+				case 0x4000: //$C000
+					nt_regs[0] = (byte)(value & 0x7F);
+					break;
+				case 0x5000: //$D000
+					nt_regs[1] = (byte)(value & 0x7F);
+					break;
+				case 0x6000: //$E000
+					flag_m = (value & 1) != 0;
+					flag_r = ((value >> 4) & 1) != 0;
+					if (flag_m) SetMirrorType(EMirrorType.Horizontal);
+					else SetMirrorType(EMirrorType.Vertical);
+					break;
+				case 0x7000: //$F000
+					prg_regs_16k[0] = value;
+					break;
+			}
+		}
+	}
+}
\ No newline at end of file
diff --git a/BizHawk.Emulation/Consoles/Nintendo/NES/iNES.cs b/BizHawk.Emulation/Consoles/Nintendo/NES/iNES.cs
index 55cc4f5093..5f811050d4 100644
--- a/BizHawk.Emulation/Consoles/Nintendo/NES/iNES.cs
+++ b/BizHawk.Emulation/Consoles/Nintendo/NES/iNES.cs
@@ -91,6 +91,7 @@ static string ClassifyTable = @"
 13	32	0	8	16	NES-CPROM; videomation
 66	64	16	8	0	NES-MHROM; super mario bros / duck hunt
 66	128	32	8	0	NES-GNROM; gumshoe
+68	128	256	8	0	SUNSOFT-4; After Burner 2 (J)
 ";
 }
 
diff --git a/BizHawk.MultiClient/output/gamedb.txt b/BizHawk.MultiClient/output/gamedb.txt
index 72b6028865..1df246dae7 100644
--- a/BizHawk.MultiClient/output/gamedb.txt
+++ b/BizHawk.MultiClient/output/gamedb.txt
@@ -2263,6 +2263,7 @@ D4448D09BBFDE687C04F9E3310E023AB		ti83_1.rom	TI83		initPC=6ce
 ;--nes--;
 ;these games seem to be in goodNES but not bootgod's DB
 sha1:22E6986903141495BA4589AC65982F3FB4D0E37B		Adventures of Lolo (U)	NES		board=NES-SEROM;PRG=32;CHR=32
+sha1:99C18C91F051BFBA6836A7B6B213C77569D83767		After Burner 2 (J)	NES		board=SUNSOFT-4;PRG=128;CHR=256;WRAM=8
 sha1:CF655333DCE649A3C7060E9989860F2FC74E473A		Demon Sword (U)	NES		board=NES-SL1ROM;PRG=128;CHR=128
 sha1:7786BA1FE8E7E9E542EEB13CF2A6E2A1AD7F696D		Metal Gear (U)	NES		board=KONAMI-UNROM;PRG=128
 sha1:894F20405286F5F75133CE4648300E2C67972B40		Solomon's Key (U)	NES		board=NES-CNROM;PRG=32;CHR=32