diff --git a/ArcFormats/ArcFormats.csproj b/ArcFormats/ArcFormats.csproj
index bfce508c..4ecbc94c 100644
--- a/ArcFormats/ArcFormats.csproj
+++ b/ArcFormats/ArcFormats.csproj
@@ -534,6 +534,7 @@
     <Compile Include="Xuse\ArcXARC.cs" />
     <Compile Include="Xuse\ArcXuse.cs" />
     <Compile Include="YaneSDK\ArcDAT.cs" />
+    <Compile Include="Yatagarasu\ArcPKG.cs" />
     <Compile Include="Youkai\ArcDAT.cs" />
     <Compile Include="Yox\ArcYOX.cs" />
     <Compile Include="Yuka\ArcYKC.cs" />
diff --git a/ArcFormats/Yatagarasu/ArcPKG.cs b/ArcFormats/Yatagarasu/ArcPKG.cs
new file mode 100644
index 00000000..06540ebf
--- /dev/null
+++ b/ArcFormats/Yatagarasu/ArcPKG.cs
@@ -0,0 +1,93 @@
+//! \file       ArcPKG.cs
+//! \date       Mon Mar 13 09:41:58 2017
+//! \brief      Yatagarasu resource archive.
+//
+// Copyright (C) 2017 by morkt
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to
+// deal in the Software without restriction, including without limitation the
+// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+// sell copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+// IN THE SOFTWARE.
+//
+
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition;
+using System.IO;
+using GameRes.Utility;
+
+namespace GameRes.Formats.Yatagarasu
+{
+    [Export(typeof(ArchiveFormat))]
+    public class PkgOpener : ArchiveFormat
+    {
+        public override string         Tag { get { return "PKG"; } }
+        public override string Description { get { return "Yatagarasu resource archive"; } }
+        public override uint     Signature { get { return 0; } }
+        public override bool  IsHierarchic { get { return false; } }
+        public override bool      CanWrite { get { return false; } }
+
+        public override ArcFile TryOpen (ArcView file)
+        {
+            if (!file.Name.EndsWith (".pkg", StringComparison.InvariantCultureIgnoreCase))
+                return null;
+            uint key = file.View.ReadUInt32 (0x84); // last bytes of the first entry name
+            if (key != file.View.ReadUInt32 (0x10C)) // keys of the first two entries supposed to be the same
+                return null;
+            int count = (int)(file.View.ReadUInt32 (4) ^ key);
+            if (!IsSaneCount (count))
+                return null;
+            var key_bytes = new byte[4];
+            LittleEndian.Pack (key, key_bytes, 0);
+            using (var input = file.CreateStream())
+            using (var dec = new ByteStringEncryptedStream (input, key_bytes))
+            using (var index = new BinaryStream (dec, file.Name))
+            {
+                index.Position = 8;
+                var dir = new List<Entry> (count);
+                for (int i = 0; i < count; ++i)
+                {
+                    var name = index.ReadCString (0x80);
+                    var entry = FormatCatalog.Instance.Create<Entry> (name);
+                    entry.Size = index.ReadUInt32();
+                    entry.Offset = index.ReadUInt32();
+                    if (!entry.CheckPlacement (file.MaxOffset))
+                        return null;
+                    dir.Add (entry);
+                }
+                return new PkgArchive (file, this, dir, key_bytes);
+            }
+        }
+
+        public override Stream OpenEntry (ArcFile arc, Entry entry)
+        {
+            var pkg_arc = (PkgArchive)arc;
+            var input = arc.File.CreateStream (entry.Offset, entry.Size);
+            return new ByteStringEncryptedStream (input, pkg_arc.Key);
+        }
+    }
+
+    internal class PkgArchive : ArcFile
+    {
+        public readonly byte[] Key;
+
+        public PkgArchive (ArcView arc, ArchiveFormat impl, ICollection<Entry> dir, byte[] key)
+            : base (arc, impl, dir)
+        {
+            Key = key;
+        }
+    }
+}