diff --git a/ArcFormats/ArcFormats.csproj b/ArcFormats/ArcFormats.csproj
index 9d215848..a5ba3ef4 100644
--- a/ArcFormats/ArcFormats.csproj
+++ b/ArcFormats/ArcFormats.csproj
@@ -125,6 +125,7 @@
     <Compile Include="NSystem\WidgetMSD.xaml.cs">
       <DependentUpon>WidgetMSD.xaml</DependentUpon>
     </Compile>
+    <Compile Include="OneUp\ArcARC.cs" />
     <Compile Include="Pandora\ImageXL24.cs" />
     <Compile Include="rUGP\ArcRIO.cs" />
     <Compile Include="Astronauts\ArcGXP.cs" />
diff --git a/ArcFormats/OneUp/ArcARC.cs b/ArcFormats/OneUp/ArcARC.cs
new file mode 100644
index 00000000..351b40f0
--- /dev/null
+++ b/ArcFormats/OneUp/ArcARC.cs
@@ -0,0 +1,76 @@
+//! \file       ArcARC.cs
+//! \date       Thu Jan 26 11:49:24 2017
+//! \brief      One-up 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.Collections.Generic;
+using System.ComponentModel.Composition;
+using System.Text;
+
+namespace GameRes.Formats.OneUp
+{
+    [Export(typeof(ArchiveFormat))]
+    public class ArcOpener : ArchiveFormat
+    {
+        public override string         Tag { get { return "ARC/ONE-UP"; } }
+        public override string Description { get { return "One-up resource archive"; } }
+        public override uint     Signature { get { return 0x43524100; } } // '\x00ARC'
+        public override bool  IsHierarchic { get { return true; } }
+        public override bool      CanWrite { get { return false; } }
+
+        public override ArcFile TryOpen (ArcView file)
+        {
+            int count = file.View.ReadInt32 (8);
+            if (!IsSaneCount (count))
+                return null;
+            uint data_offset = file.View.ReadUInt32 (4);
+            if (data_offset >= file.MaxOffset)
+                return null;
+
+            var name_buf = new byte[0x100];
+            var dir = new List<Entry> (count);
+            uint index_offset = 0xC;
+            for (int i = 0; i < count; ++i)
+            {
+                uint name_length = file.View.ReadUInt32 (index_offset);
+                index_offset += 4;
+                if (name_length > 0x400)
+                    return null;
+                if (name_length > (uint)name_buf.Length)
+                    name_buf = new byte[name_length];
+                file.View.Read (index_offset, name_buf, 0, name_length);
+                var name = Encoding.Unicode.GetString (name_buf, 0, (int)name_length);
+                index_offset += name_length;
+                var entry = FormatCatalog.Instance.Create<Entry> (name);
+                entry.Offset = data_offset;
+                entry.Size = file.View.ReadUInt32 (index_offset);
+                if (!entry.CheckPlacement (file.MaxOffset))
+                    return null;
+                dir.Add (entry);
+                data_offset += entry.Size;
+                index_offset += 4;
+            }
+            return new ArcFile (file, this, dir);
+        }
+    }
+}
diff --git a/supported.html b/supported.html
index e0e7963c..3d35b97c 100644
--- a/supported.html
+++ b/supported.html
@@ -248,6 +248,7 @@ Astelight series<br/>
 <tr class="odd last"><td>*.lim</td><td><tt>LM</tt></td><td>No</td></tr>
 <tr><td>*.xp3</td><td><tt>XP3</tt></td><td>Yes</td><td rowspan="2">KiriKiri</td><td rowspan="2">
 11eyes<br/>
+Ah, Ojou-sama<br/>
 Altered Pink ~Tokumu Sentai Duel Ranger~<br/>
 Amairo＊Islenauts<br/>
 Aozora Gakko no Sensei-kun<br/>
@@ -309,6 +310,7 @@ Suiheisen made Nan Mile?<br/>
 Swan Song<br/>
 Teakamamire no Tenshi<br/>
 Towazugatari ~Shoujo Ryoujoku Hishou~<br/>
+With Ribbon<br/>
 Yomibito Shirazu ~Amai Meshibe no Seichoushi~<br/>
 Yuugu ~Nyomitsu Gangu Adesugata~<br/>
 Yuugu 2 ~Dai Ni Kinsho no Nozomu Mono~<br/>
@@ -458,6 +460,7 @@ Intruder <span class="footnote">ShiinaRio v2.49</span><br/>
 Itsuka, Dokoka de ~Ano Ameoto no Kioku~<span class="footnote">2.36 or 2.37</span><br/>
 Kateinai Choukyou <span class="footnote">ShiinaRio v2.31</span><br/>
 Kichiku Nakadashi Suieibu<span class="footnote">ShiinaRio v2.41</span><br/>
+Last Waltz ~Hakudaku Mamire no Natsu Gasshuku~ <span class="footnote">ShiinaRio v2.47</span><br/>
 Mahou Shoujo no Taisetsu na Koto <span class="footnote">ShiinaRio v2.47</span><br/>
 Maki Fes! <span class="footnote">ShiinaRio v2.50</span><br/>
 Mikoko <span class="footnote">ShiinaRio v2.46</span><br/>
@@ -1379,6 +1382,9 @@ Kidou Houshinki<br/>
 Shoujo Kyouiku<br/>
 Shoukoujo<br/>
 </td></tr>
+<tr><td>*.arc</td><td><tt>\x00ARC</tt></td><td>No</td><td>One-up</td><td>
+Dedenden!<br/>
+</td></tr>
 </table>
 <p><a name="note-1" class="footnote">1</a> Non-encrypted only</p>
 </body>