diff --git a/src/Aiursoft.ChessServer/Models/AcceptedChallenge.cs b/src/Aiursoft.ChessServer/Models/AcceptedChallenge.cs
new file mode 100644
index 0000000..b7ff47b
--- /dev/null
+++ b/src/Aiursoft.ChessServer/Models/AcceptedChallenge.cs
@@ -0,0 +1,59 @@
+using Aiursoft.AiurObserver;
+
+namespace Aiursoft.ChessServer.Models;
+
+public class AcceptedChallenge : Challenge
+{
+    private readonly bool _creatorIsWhite;
+    public AcceptedChallenge(
+        Player creator, 
+        Player accepter, 
+        string message, 
+        RoleRule roleRule, 
+        TimeSpan timeLimit, 
+        ChallengePermission permission,
+        AsyncObservable<string> challengeChangedChannel)
+        : base(creator, message, roleRule, timeLimit, permission)
+    {
+        Accepter = accepter;
+        Game = new Game();
+        ChallengeChangedChannel = challengeChangedChannel;
+        _creatorIsWhite = RoleRule switch
+        {
+            RoleRule.Random => new Random().Next(0, 2) == 0,
+            RoleRule.CreatorWhite => true,
+            RoleRule.AccepterWhite => false,
+            _ => _creatorIsWhite
+        };
+    }
+
+    public Player Accepter { get; set; }
+    public Game Game { get; set; }
+    
+    public AsyncObservable<ChatMessage> ChatChannel { get; init; } = new();
+    
+    public Player GetWhitePlayer() => _creatorIsWhite ? Creator : Accepter;
+    public Player GetBlackPlayer() => _creatorIsWhite ? Accepter : Creator;
+    
+    public DateTime GameStartTime { get; set; } = DateTime.UtcNow;
+
+    public Player GetTurnPlayer()
+    {
+        return Game.Board.Turn.AsChar.ToString().Equals("w", StringComparison.CurrentCultureIgnoreCase) 
+            ? GetWhitePlayer() : GetBlackPlayer(); 
+    }
+
+    public string GetPlayerColor(Guid playerId)
+    {
+        // returns : w,b, or m (monitor)
+        if (GetWhitePlayer().Id == playerId)
+        {
+            return "w";
+        }
+        if (GetBlackPlayer().Id == playerId)
+        {
+            return "b";
+        }
+        return "m";
+    }
+}
\ No newline at end of file
diff --git a/src/Aiursoft.ChessServer/Models/Challenge.cs b/src/Aiursoft.ChessServer/Models/Challenge.cs
index c069607..6da9bb1 100644
--- a/src/Aiursoft.ChessServer/Models/Challenge.cs
+++ b/src/Aiursoft.ChessServer/Models/Challenge.cs
@@ -26,73 +26,4 @@ public class Challenge(
     // Creator transferred: creator-transferred-{new-owner-player-nick-name}
     // Settings changed: settings-changed
     public AsyncObservable<string> ChallengeChangedChannel { get; protected init; } = new();
-}
-
-public class AcceptedChallenge : Challenge
-{
-    private readonly bool _creatorIsWhite;
-    public AcceptedChallenge(
-        Player creator, 
-        Player accepter, 
-        string message, 
-        RoleRule roleRule, 
-        TimeSpan timeLimit, 
-        ChallengePermission permission,
-        AsyncObservable<string> challengeChangedChannel)
-        : base(creator, message, roleRule, timeLimit, permission)
-    {
-        Accepter = accepter;
-        Game = new Game();
-        ChallengeChangedChannel = challengeChangedChannel;
-        _creatorIsWhite = RoleRule switch
-        {
-            RoleRule.Random => new Random().Next(0, 2) == 0,
-            RoleRule.CreatorWhite => true,
-            RoleRule.AccepterWhite => false,
-            _ => _creatorIsWhite
-        };
-    }
-
-    public Player Accepter { get; set; }
-    public Game Game { get; set; }
-    
-    public AsyncObservable<ChatMessage> ChatChannel { get; init; } = new();
-    
-    public Player GetWhitePlayer() => _creatorIsWhite ? Creator : Accepter;
-    public Player GetBlackPlayer() => _creatorIsWhite ? Accepter : Creator;
-    
-    public DateTime GameStartTime { get; set; } = DateTime.UtcNow;
-
-    public Player GetTurnPlayer()
-    {
-        return Game.Board.Turn.AsChar.ToString().Equals("w", StringComparison.CurrentCultureIgnoreCase) 
-            ? GetWhitePlayer() : GetBlackPlayer(); 
-    }
-
-    public string GetPlayerColor(Guid playerId)
-    {
-        // returns : w,b, or m (monitor)
-        if (GetWhitePlayer().Id == playerId)
-        {
-            return "w";
-        }
-        if (GetBlackPlayer().Id == playerId)
-        {
-            return "b";
-        }
-        return "m";
-    }
-}
-
-public class ChatMessage(string content, Player sender)
-{
-    public string Content { get; set; } = content;
-    public Player Sender { get; set; } = sender;
-}
-
-public class ChatMessageResponse(ChatMessage message, Guid currentUserId)
-{
-    public string Content { get; set; } = message.Content;
-    public string SenderNickName { get; set; } = message.Sender.NickName;
-    public bool IsMe { get; set; } = message.Sender.Id == currentUserId;
 }
\ No newline at end of file
diff --git a/src/Aiursoft.ChessServer/Models/ChatMessage.cs b/src/Aiursoft.ChessServer/Models/ChatMessage.cs
new file mode 100644
index 0000000..b493a73
--- /dev/null
+++ b/src/Aiursoft.ChessServer/Models/ChatMessage.cs
@@ -0,0 +1,7 @@
+namespace Aiursoft.ChessServer.Models;
+
+public class ChatMessage(string content, Player sender)
+{
+    public string Content { get; set; } = content;
+    public Player Sender { get; set; } = sender;
+}
\ No newline at end of file
diff --git a/src/Aiursoft.ChessServer/Models/ChatMessageResponse.cs b/src/Aiursoft.ChessServer/Models/ChatMessageResponse.cs
new file mode 100644
index 0000000..3d3b10c
--- /dev/null
+++ b/src/Aiursoft.ChessServer/Models/ChatMessageResponse.cs
@@ -0,0 +1,8 @@
+namespace Aiursoft.ChessServer.Models;
+
+public class ChatMessageResponse(ChatMessage message, Guid currentUserId)
+{
+    public string Content { get; set; } = message.Content;
+    public string SenderNickName { get; set; } = message.Sender.NickName;
+    public bool IsMe { get; set; } = message.Sender.Id == currentUserId;
+}
\ No newline at end of file