What is Combine Chess?

Combine Chess is a revolutionary chess variant where players can merge compatible pieces (like Rook + Bishop) into powerful hybrid pieces, adding new strategic dimensions to traditional chess.

How do I combine pieces?

Double-tap a piece or use the Combine Mode button to see available combinations. Compatible pieces within reach can be merged into hybrid pieces with combined movement abilities.

Can I play against AI?

Yes! Combine Chess features advanced AI opponents with multiple difficulty levels (Easy, Medium, Hard) that understand both traditional chess and hybrid piece mechanics.

Is multiplayer available?

Absolutely! Play real-time multiplayer games using peer-to-peer WebRTC technology. No servers required - connect directly with friends anywhere in the world.

Official Combine Chess Rules

Complete rulebook for the revolutionary chess variant with hybrid piece mechanics

1. Foundation Rules

Combine Chess is built upon standard chess with additional mechanics:

All FIDE chess rules apply unless specifically modified
Standard 8x8 board with traditional starting position
Same objective: checkmate the opponent's king
All traditional moves (castling, en passant, promotion) remain valid
Additional mechanics: piece combination and decombination

2. Piece Combination Rules

2.1 Eligible Combinations

Rook + Bishop → Rook-Bishop Hybrid (RB)
Rook + Knight → Rook-Knight Hybrid (RN)
Bishop + Knight → Bishop-Knight Hybrid (BN)
Queen + Knight → Queen-Knight Hybrid (QN)

2.2 Combination Requirements

Both pieces must belong to the same player
Pieces must be within each other's movement range
The player must not be in check
The combination square must be unoccupied or contain an opponent piece (capture)
The resulting position must not leave the king in check

2.3 Combination Process

Select the first piece (becomes the anchor)
Select the second compatible piece within range
Choose the destination square (either piece's current position)
Both original pieces are removed, hybrid piece is placed
If an opponent piece is captured, it's removed from the board
Turn passes to the opponent

3. Hybrid Piece Movement

Rook-Bishop (RB)

Moves like both Rook and Bishop - combines horizontal/vertical with diagonal movement (essentially a Queen)

Rook-Knight (RN)

Moves like Rook (horizontal/vertical) OR Knight (L-shaped jumps)

Bishop-Knight (BN)

Moves like Bishop (diagonal) OR Knight (L-shaped jumps)

Queen-Knight (QN)

Moves like Queen (any direction) OR Knight (L-shaped jumps) - the most powerful piece

4. Decombination Rules

4.1 Decombination Process

Select a hybrid piece to decombine
Choose an adjacent empty square for one component
The other component remains on the hybrid's square
Player chooses which component goes where
Cannot decombine if it would leave the king in check

4.2 Decombination Restrictions

Must have at least one adjacent empty square
Cannot decombine while in check
Cannot decombine if it exposes the king to check
Decombination counts as one move

5. Special Situations

5.1 Check and Checkmate

Hybrid pieces can give check using any of their movement abilities
Kings can be checkmated by hybrid pieces
Combinations and decombinations can be used to escape check
Standard checkmate and stalemate rules apply

5.2 Pawn Promotion

Pawns can promote to any standard piece (Q, R, B, N)
Pawns cannot promote directly to hybrid pieces
Promoted pieces can immediately be used for combinations

5.3 Castling

Standard castling rules apply
Hybrid pieces cannot castle (they're not kings or rooks)
If a rook becomes part of a hybrid, castling rights are lost

Tournament Play

For competitive play, standard chess tournament rules apply with these additions:

Time controls follow standard chess formats
Combination and decombination each count as one move
Players must clearly announce hybrid piece movements
Standard notation extended to include combination symbols

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