diff --git a/source/World/RegionFile.cpp b/source/World/RegionFile.cpp
new file mode 100644
index 0000000..72c169d
--- /dev/null
+++ b/source/World/RegionFile.cpp
@@ -0,0 +1,166 @@
+#include "RegionFile.hpp"
+
+#define SECTOR_BYTES (4096)
+
+static void void_sub(int a, int b)
+{
+}
+
+#define WRITE(data, elemsize, elemcnt, file) void_sub(int(fwrite(data, elemsize, elemcnt, file)), elemcnt)
+#define READ( data, elemsize, elemcnt, file) void_sub(int(fread (data, elemsize, elemcnt, file)), elemcnt)
+
+RegionFile::RegionFile(const std::string fileName)
+{
+	m_fileName = fileName + "/" + "chunks.dat";
+
+	field_20 = new int[1024];
+	field_24 = new int[1024];
+	memset(field_20, 0, 1024 * sizeof(int));
+}
+
+RegionFile::~RegionFile()
+{
+	close();
+	if (field_20) delete[] field_20;
+	if (field_24) delete[] field_24;
+}
+
+void RegionFile::close()
+{
+	if (m_pFile)
+	{
+		fclose(m_pFile);
+		m_pFile = nullptr;
+	}
+}
+
+bool RegionFile::open()
+{
+	close();
+	memset(field_20, 0, 1024 * sizeof(int));
+	
+	m_pFile = fopen(m_fileName.c_str(), "r+b");
+	if (m_pFile)
+	{
+		READ(field_20, sizeof(int), 1024, m_pFile);
+		
+		field_28[0] = false;
+
+		for (int i = 0; i < 1024; i++)
+		{
+			if (field_20[i])
+			{
+				for (int j = 0; j < uint8_t(field_20[i]); j++)
+				{
+					field_28[j + (field_20[i] >> 8)] = false;
+				}
+			}
+		}
+
+		return m_pFile != nullptr;
+	}
+
+	m_pFile = fopen(m_fileName.c_str(), "w+b");
+	if (!m_pFile)
+		return false;
+
+	WRITE(field_20, sizeof(int), 1024, m_pFile);
+	field_28[0] = false;
+}
+
+bool RegionFile::readChunk(int x, int z, RakNet::BitStream** pBitStream)
+{
+	int idx = field_20[32 * z + x];
+	if (!idx)
+		return false;
+
+	int length = 0;
+	fseek(m_pFile, (idx >> 8) * SECTOR_BYTES, SEEK_SET);
+	fread(&length, sizeof(int), 1, m_pFile);
+	
+	assert(length < ((offset & 0xff) * SECTOR_BYTES));
+
+	length -= 4;
+
+	uint8_t* data = new uint8_t[length];
+	READ(data, 1, length, m_pFile);
+
+	*pBitStream = new RakNet::BitStream(data, length, false);
+	return true;
+}
+
+bool RegionFile::write(int index, RakNet::BitStream& bitStream)
+{
+	fseek(m_pFile, index * SECTOR_BYTES, 0);
+	int length = sizeof(int) + bitStream.GetNumberOfBytesUsed();
+
+	WRITE(&length, sizeof(length), 1, m_pFile);
+	WRITE(bitStream.GetData(), 1, bitStream.GetNumberOfBytesUsed(), m_pFile);
+
+	return true;
+}
+
+bool RegionFile::writeChunk(int x, int z, RakNet::BitStream& bitStream)
+{
+	int length = bitStream.GetNumberOfBytesUsed();
+	int field20i = field_20[32 * z + x];
+	int lowerIndex = (length + 4) / SECTOR_BYTES;
+	if (lowerIndex > 256)
+		return false;
+
+	int field20iU = field20i >> 8, field20iL = field20i & 0xff;
+
+	if (field20iU && lowerIndex == field20iL)
+	{
+		write(field20iU, bitStream);
+		return true;
+	}
+	
+	for (int i = 0; i < field20iL; i++)
+	{
+		field_28[i + field20iU] = true;
+	}
+
+	bool bNeedWrite = false;
+	int v22 = 0, i = 0;
+	while (i < lowerIndex)
+	{
+		if (field_28.find(i + v22) == field_28.end())
+		{
+			bNeedWrite = true;
+			break;
+		}
+
+		if (field_28[i + v22])
+		{
+			i++;
+		}
+		else
+		{
+			v22 += i + 1;
+			i = 0;
+		}
+	}
+
+	if (bNeedWrite)
+	{
+		fseek(m_pFile, 0, SEEK_END);
+		for (int j = 0; lowerIndex - i > j; j++)
+		{
+			fwrite(field_24, sizeof(int), 1024, m_pFile);
+			field_28[j + v22] = true;
+		}
+	}
+
+	field_20[32 * z + x] = (v22 << 8) | lowerIndex;
+	for (int k = 0; k < lowerIndex; k++)
+	{
+		field_28[k + v22] = false;
+	}
+
+	write(v22, bitStream);
+	fseek(m_pFile, sizeof(int) * (x + 32 * z), SEEK_SET);
+	fwrite(&field_20[x + 32 * z], sizeof(int), 1, m_pFile);
+
+	return true;
+}
diff --git a/source/World/RegionFile.hpp b/source/World/RegionFile.hpp
new file mode 100644
index 0000000..0b873f2
--- /dev/null
+++ b/source/World/RegionFile.hpp
@@ -0,0 +1,27 @@
+#pragma once
+
+#include <cstdio>
+#include <string>
+#include <cassert>
+#include <map>
+#include "BitStream.h"
+
+class RegionFile
+{
+public:
+	RegionFile(const std::string fileName);
+	~RegionFile();
+	void close();
+	bool open();
+	bool readChunk(int x, int z, RakNet::BitStream**);
+	bool write(int index, RakNet::BitStream&);
+	bool writeChunk(int x, int z, RakNet::BitStream&);
+
+public:
+	FILE* m_pFile = nullptr;
+	std::string m_fileName;
+	int* field_20;
+	int* field_24;
+	std::map<int, bool> field_28;
+};
+
diff --git a/windows_vs/minecraftcpp.vcxproj b/windows_vs/minecraftcpp.vcxproj
index 4d0638b..8acb945 100644
--- a/windows_vs/minecraftcpp.vcxproj
+++ b/windows_vs/minecraftcpp.vcxproj
@@ -137,6 +137,7 @@
     <ClInclude Include="..\source\World\Particle\Particle.hpp" />
     <ClInclude Include="..\source\World\Particle\ParticleEngine.hpp" />
     <ClInclude Include="..\source\World\Region.hpp" />
+    <ClInclude Include="..\source\World\RegionFile.hpp" />
     <ClInclude Include="..\source\World\Renderer\Chunk.hpp" />
     <ClInclude Include="..\source\World\Renderer\Culler.hpp" />
     <ClInclude Include="..\source\World\Renderer\EntityRenderDispatcher.hpp" />
@@ -454,6 +455,7 @@
     <ClCompile Include="..\source\World\Particle\SmokeParticle.cpp" />
     <ClCompile Include="..\source\World\Particle\TerrainParticle.cpp" />
     <ClCompile Include="..\source\World\Region.cpp" />
+    <ClCompile Include="..\source\World\RegionFile.cpp" />
     <ClCompile Include="..\source\World\Renderer\Chunk.cpp" />
     <ClCompile Include="..\source\World\Renderer\Culler.cpp" />
     <ClCompile Include="..\source\World\Renderer\EntityRenderDispatcher.cpp" />
diff --git a/windows_vs/minecraftcpp.vcxproj.filters b/windows_vs/minecraftcpp.vcxproj.filters
index 1c93f6a..94636be 100644
--- a/windows_vs/minecraftcpp.vcxproj.filters
+++ b/windows_vs/minecraftcpp.vcxproj.filters
@@ -1059,6 +1059,9 @@
     <ClCompile Include="..\platforms\windows\SoundSystem_windows.cpp">
       <Filter>Source Files\App</Filter>
     </ClCompile>
+    <ClCompile Include="..\source\World\RegionFile.cpp">
+      <Filter>Source Files\World</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="..\source\Options.hpp">
@@ -1925,6 +1928,9 @@
     <ClInclude Include="..\GameMods.hpp">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="..\source\World\RegionFile.hpp">
+      <Filter>Header Files\World</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <Text Include="..\thirdparty\raknet\CMakeLists.txt">