diff --git a/Legacy/Sogna/ArcSGS.cs b/Legacy/Sogna/ArcSGS.cs
new file mode 100644
index 00000000..ed540a87
--- /dev/null
+++ b/Legacy/Sogna/ArcSGS.cs
@@ -0,0 +1,113 @@
+//! \file       ArcSGS.cs
+//! \date       2018 Jul 19
+//! \brief      Sogna resource archive.
+//
+// Copyright (C) 2018 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.Collections.Generic;
+using System.ComponentModel.Composition;
+using System.IO;
+using GameRes.Utility;
+
+// [030320][Sogna] Viper-V6 R
+
+namespace GameRes.Formats.Sogna
+{
+    [Export(typeof(ArchiveFormat))]
+    public class SgsDatOpener : ArchiveFormat
+    {
+        public override string         Tag { get { return "DAT/SGS"; } }
+        public override string Description { get { return "Sogna resource archive"; } }
+        public override uint     Signature { get { return 0x2E534753; } } // 'SGS.DAT 1.00'
+        public override bool  IsHierarchic { get { return true; } }
+        public override bool      CanWrite { get { return false; } }
+
+        public override ArcFile TryOpen (ArcView file)
+        {
+            if (!file.View.AsciiEqual (4, "DAT 1.00"))
+                return null;
+            int count = file.View.ReadInt32 (12);
+            if (!IsSaneCount (count))
+                return null;
+
+            uint index_offset = 0x10;
+            var dir = new List<Entry> (count);
+            for (int i = 0; i < count; ++i)
+            {
+                var name = file.View.ReadString (index_offset, 0x10);
+                var entry = FormatCatalog.Instance.Create<PackedEntry> (name);
+                entry.IsPacked      = file.View.ReadByte (index_offset+0x13) != 0;
+                entry.Size          = file.View.ReadUInt32 (index_offset+0x14);
+                entry.UnpackedSize  = file.View.ReadUInt32 (index_offset+0x18);
+                entry.Offset        = file.View.ReadUInt32 (index_offset+0x1C);
+                if (!entry.CheckPlacement (file.MaxOffset))
+                    return null;
+                dir.Add (entry);
+                index_offset += 0x20;
+            }
+            return new ArcFile (file, this, dir);
+        }
+
+        public override Stream OpenEntry (ArcFile arc, Entry entry)
+        {
+            var pent = entry as PackedEntry;
+            if (null == pent || !pent.IsPacked)
+                return base.OpenEntry (arc, entry);
+            using (var input = arc.File.CreateStream (entry.Offset, entry.Size))
+            {
+                var output = new byte[pent.UnpackedSize];
+                LzUnpack (input, output);
+                return new BinMemoryStream (output, entry.Name);
+            }
+        }
+
+        void LzUnpack (IBinaryStream input, byte[] output)
+        {
+            int dst = 0;
+            int bits = 0;
+            byte mask = 0;
+            while (dst < output.Length)
+            {
+                mask >>= 1;
+                if (0 == mask)
+                {
+                    bits = input.ReadByte();
+                    if (-1 == bits)
+                        break;
+                    mask = 0x80;
+                }
+                if ((mask & bits) != 0)
+                {
+                    int offset = input.ReadUInt16();
+                    int count = (offset >> 12) + 1;
+                    offset &= 0xFFF;
+                    Binary.CopyOverlapped (output, dst-offset, dst, count);
+                    dst += count;
+                }
+                else
+                {
+                    output[dst++] = input.ReadUInt8();
+                }
+            }
+        }
+    }
+}