diff --git a/Core/Core.vcxproj b/Core/Core.vcxproj
index 10180300..dc976b92 100644
--- a/Core/Core.vcxproj
+++ b/Core/Core.vcxproj
@@ -541,6 +541,7 @@
     <ClInclude Include="Kaiser7017.h" />
     <ClInclude Include="Kaiser7031.h" />
     <ClInclude Include="KeyManager.h" />
+    <ClInclude Include="Lh51.h" />
     <ClInclude Include="Mapper116.h" />
     <ClInclude Include="MMC3_198.h" />
     <ClInclude Include="MMC3_208.h" />
diff --git a/Core/Core.vcxproj.filters b/Core/Core.vcxproj.filters
index f3e87554..2025f63e 100644
--- a/Core/Core.vcxproj.filters
+++ b/Core/Core.vcxproj.filters
@@ -1450,6 +1450,9 @@
     <ClInclude Include="Gkcx1.h">
       <Filter>Nes\Mappers\Unif</Filter>
     </ClInclude>
+    <ClInclude Include="Lh51.h">
+      <Filter>Nes\Mappers\Unif</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="stdafx.cpp">
diff --git a/Core/Lh51.h b/Core/Lh51.h
new file mode 100644
index 00000000..96efa5f9
--- /dev/null
+++ b/Core/Lh51.h
@@ -0,0 +1,32 @@
+#pragma once
+#include "stdafx.h"
+#include "BaseMapper.h"
+
+class Lh51 : public BaseMapper
+{
+protected:
+	virtual uint16_t GetPRGPageSize() override { return 0x2000; }
+	virtual uint16_t GetCHRPageSize() override { return 0x2000; }
+
+	void InitMapper() override
+	{
+		SelectPRGPage(0, 0);
+		SelectPRGPage(1, 13);
+		SelectPRGPage(2, 14);
+		SelectPRGPage(3, 15);
+		SelectCHRPage(0, 0);
+	}
+
+	void WriteRegister(uint16_t addr, uint8_t value) override
+	{
+		switch(addr & 0xE000) {
+			case 0x8000:
+				SelectPRGPage(0, value & 0x0F);
+				break;
+
+			case 0xE000:
+				SetMirroringType(value & 0x08 ? MirroringType::Horizontal : MirroringType::Vertical);
+				break;
+		}
+	}
+};
diff --git a/Core/MapperFactory.cpp b/Core/MapperFactory.cpp
index 83863d51..0c1a48ff 100644
--- a/Core/MapperFactory.cpp
+++ b/Core/MapperFactory.cpp
@@ -88,6 +88,7 @@
 #include "Kaiser7058.h"
 #include "Lh10.h"
 #include "Lh32.h"
+#include "Lh51.h"
 #include "Malee.h"
 #include "MagicKidGooGoo.h"
 #include "Mapper15.h"
@@ -576,7 +577,7 @@ BaseMapper* MapperFactory::GetMapperFromID(RomData &romData)
 		case 306: return new Kaiser7016();
 		case 307: return new Kaiser7037();
 		case 308: break; //TH2131-1
-		case 309: break; //LH51
+		case 309: return new Lh51();
 		//310-311
 		case 312: return new Kaiser7013B();
 		case 313: break; //RESET-TXROM
diff --git a/Core/UnifLoader.cpp b/Core/UnifLoader.cpp
index b90bba8d..8e19db91 100644
--- a/Core/UnifLoader.cpp
+++ b/Core/UnifLoader.cpp
@@ -67,6 +67,7 @@ std::unordered_map<string, int> UnifLoader::_boardMappings = std::unordered_map<
 	{ "LE05", UnifBoards::UnknownBoard },
 	{ "LH10", 522 },
 	{ "LH32", 125 },
+	{ "LH51", 309 },
 	{ "LH53", UnifBoards::UnknownBoard },
 	{ "MALISB", 325 },
 	{ "MARIO1-MALEE2", UnifBoards::Malee },