diff --git a/anvil-loader/src/main/java/mc/world/anvil/Region.java b/anvil-loader/src/main/java/mc/world/anvil/Region.java
index 794d27f..b171aee 100644
--- a/anvil-loader/src/main/java/mc/world/anvil/Region.java
+++ b/anvil-loader/src/main/java/mc/world/anvil/Region.java
@@ -51,7 +51,7 @@ class Region implements Closeable {
     Chunk getChunk(int x, int z) {
         int offset;
         try {
-            offset = getOffset(x, z);
+            offset = getOffset(x & 31, z & 31);
         } catch (Exception e) {
             return new EmptyChunk(x, z);
         }
diff --git a/anvil-loader/src/test/java/mc/world/anvil/RegionTest.java b/anvil-loader/src/test/java/mc/world/anvil/RegionTest.java
index d7ea2b1..88fa1b3 100644
--- a/anvil-loader/src/test/java/mc/world/anvil/RegionTest.java
+++ b/anvil-loader/src/test/java/mc/world/anvil/RegionTest.java
@@ -21,19 +21,30 @@ import java.util.List;
 import java.util.stream.Stream;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 
 class RegionTest {
-    private static Region region;
+    private static RegionManager regionManager;
 
     @BeforeAll
     @SneakyThrows
     static void before() {
-        region = new Region(Paths.get(RegionTest.class.getResource("/region/r.0.0.mca").toURI()).toFile());
+        regionManager = new RegionManager(Paths.get(RegionTest.class.getResource("/region/").toURI()));
     }
 
-    private static Stream<Arguments> streamArguments() {
-        ChunkChecker chunkChecker00 = new ChunkChecker() {
+    private static void assertZeroPlast(int x, int z, Block block, String msg) {
+        // @formatter:off
+        if      (x ==  0 && z ==  0) assertEquals(BlockType.STONE, block.getType(), msg);
+        else if (x == 15 && z ==  0) assertEquals(BlockType.GRANITE, block.getType(), msg);
+        else if (x ==  0 && z == 15) assertEquals(BlockType.POLISHED_GRANITE, block.getType(), msg);
+        else if (x == 15 && z == 15) assertEquals(BlockType.DIORITE, block.getType(), msg);
+        else                         assertEquals(BlockType.BEDROCK, block.getType(), msg);
+        // @formatter:on
+    }
+
+    private static ChunkChecker chunkChecker00() {
+        return new ChunkChecker() {
             private void checkSection0(ChunkSection chunkSection) {
                 for (int y = 0; y < 16; y++) {
                     for (int x = 0; x < 16; x++) {
@@ -42,13 +53,7 @@ class RegionTest {
                             String msg = String.format("coords: %d %d %d", x, y, z);
 
                             if (y == 0) {
-                                // @formatter:off
-                                if      (x ==  0 && z ==  0) assertEquals(BlockType.STONE, block.getType(), msg);
-                                else if (x == 15 && z ==  0) assertEquals(BlockType.GRANITE, block.getType(), msg);
-                                else if (x ==  0 && z == 15) assertEquals(BlockType.POLISHED_GRANITE, block.getType(), msg);
-                                else if (x == 15 && z == 15) assertEquals(BlockType.DIORITE, block.getType(), msg);
-                                else                         assertEquals(BlockType.BEDROCK, block.getType(), msg);
-                                // @formatter:on
+                                assertZeroPlast(x, z, block, msg);
                             } else {
                                 assertEquals(BlockType.STONE, block.getType(), msg);
                             }
@@ -112,8 +117,10 @@ class RegionTest {
                 checkSection1(chunkSection);
             }
         };
+    }
 
-        ChunkChecker chunkChecker01 = new ChunkChecker() {
+    private static ChunkChecker chunkChecker01() {
+        return new ChunkChecker() {
             @Override
             public void check(Chunk chunk) {
                 ChunkSection section = chunk.getChunkSection(0);
@@ -145,13 +152,7 @@ class RegionTest {
                             String msg = String.format("coords: %d %d %d", x, y, z);
 
                             if (y == 0) {
-                                // @formatter:off
-                                if      (x ==  0 && z ==  0) assertEquals(BlockType.STONE, block.getType(), msg);
-                                else if (x == 15 && z ==  0) assertEquals(BlockType.GRANITE, block.getType(), msg);
-                                else if (x ==  0 && z == 15) assertEquals(BlockType.POLISHED_GRANITE, block.getType(), msg);
-                                else if (x == 15 && z == 15) assertEquals(BlockType.DIORITE, block.getType(), msg);
-                                else                         assertEquals(BlockType.BEDROCK, block.getType(), msg);
-                                // @formatter:on
+                                assertZeroPlast(x, z, block, msg);
                             } else {
                                 assertEquals(exceptedTypes.get(x), block.getType(), msg);
                             }
@@ -160,10 +161,35 @@ class RegionTest {
                 }
             }
         };
+    }
+
+    private static ChunkChecker chunkChecker0N1() {
+        return new ChunkChecker() {
+            @Override
+            public void check(Chunk chunk) {
+                ChunkSection section = chunk.getChunkSection(0);
+                assertNotNull(section);
+
+                for (int y = 0; y < 1; y++) {
+                    for (int x = 0; x < 16; x++) {
+                        for (int z = 0; z < 16; z++) {
+                            assertZeroPlast(x, z,
+                                    section.getBlock(x, y, z),
+                                    String.format("coords: %d %d %d", x, y, z));
+                        }
+                    }
+                }
+            }
+        };
+    }
+
+    private static Stream<Arguments> streamArguments() {
+
 
         return Stream.of(
-                Arguments.of(0, 0, chunkChecker00),
-                Arguments.of(0, 1, chunkChecker01)
+                Arguments.of(0, 0, chunkChecker00()),
+                Arguments.of(0, 1, chunkChecker01()),
+                Arguments.of(0, -1, chunkChecker0N1())
         );
     }
 
@@ -171,8 +197,12 @@ class RegionTest {
     @ParameterizedTest(name = "[{index}] chunk {0},{1}")
     @MethodSource("streamArguments")
     void testGetChunk(int chunkX, int chunkZ, ChunkChecker chunkChecker) {
+        final Region region = regionManager.getRegion(chunkX >> 5, chunkZ >> 5);
+        assertNotNull(region);
+
         final Chunk chunk = region.getChunk(chunkX, chunkZ);
         assertNotNull(chunk);
+        assertFalse(chunk instanceof EmptyChunk);
 
         chunkChecker.check(chunk);
     }
diff --git a/anvil-loader/src/test/resources/region/r.0.-1.mca b/anvil-loader/src/test/resources/region/r.0.-1.mca
new file mode 100644
index 0000000..25001f9
Binary files /dev/null and b/anvil-loader/src/test/resources/region/r.0.-1.mca differ