diff --git a/Legacy/Nyoken/ArcZLK.cs b/Legacy/Nyoken/ArcZLK.cs
new file mode 100644
index 00000000..9e44d647
--- /dev/null
+++ b/Legacy/Nyoken/ArcZLK.cs
@@ -0,0 +1,84 @@
+//! \file       ArcZLK.cs
+//! \date       2019 Jan 03
+//! \brief      Nyotai Kougaku Kenkyuujo resource archive.
+//
+// Copyright (C) 2019 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.Compression;
+
+namespace GameRes.Formats.Nyoken
+{
+    [Export(typeof(ArchiveFormat))]
+    public class ZlkOpener : ArchiveFormat
+    {
+        public override string         Tag { get { return "ZLK"; } }
+        public override string Description { get { return "Nyotai Kougaku Kenkyuujo resource archive"; } }
+        public override uint     Signature { get { return 0x204B4C5A; } } // 'ZLK '
+        public override bool  IsHierarchic { get { return false; } }
+        public override bool      CanWrite { get { return false; } }
+
+        public override ArcFile TryOpen (ArcView file)
+        {
+            int version = file.View.ReadInt32 (4);
+            if (version <= 0 || version > 100)
+                return null;
+            int count = file.View.ReadInt32 (8);
+            if (!IsSaneCount (count))
+                return null;
+
+            uint index_offset = 12;
+            var dir = new List<Entry> (count);
+            for (int i = 0; i < count; ++i)
+            {
+                uint offset = file.View.ReadUInt32 (index_offset);
+                uint size1  = file.View.ReadUInt32 (index_offset+4);
+                uint size2  = file.View.ReadUInt32 (index_offset+8);
+                byte flags  = file.View.ReadByte (index_offset+12);
+                byte name_length = file.View.ReadByte (index_offset+13);
+                index_offset += 14;
+                var name = file.View.ReadString (index_offset, name_length);
+                index_offset += name_length;
+                var entry = Create<PackedEntry> (name);
+                entry.Offset = offset;
+                entry.Size   = size1;
+                entry.UnpackedSize = size2;
+                entry.IsPacked = flags != 0;
+                if (!entry.CheckPlacement (file.MaxOffset))
+                    return null;
+                dir.Add (entry);
+            }
+            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);
+            var input = arc.File.CreateStream (entry.Offset, entry.Size);
+            return new ZLibStream (input, CompressionMode.Decompress);
+        }
+    }
+}