Flanking Zone Field of Battle (FZFOB) Chess

FZFOB Chess is a new 10×10 chess variant that builds on the rules of classical chess and Chess960. It introduces a surrounding “Flanking Zone” that only knights can enter, expanding the board without overcomplicating the game. The result is a tactically rich variant with new opening dynamics, creative mobility, and minimal rule changes.

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📌 Variant Summary

• The game is played on a 10×10 board.
• The inner 8×8 grid (a1–h8) is the Field of Battle (FOB), where all traditional rules apply.
• The surrounding ring (files θ and χ, and ranks 0 and 9) is the Flanking Zone, accessible only by knights.
• All non-knight pieces must remain inside the FOB at all times.
• Opening theory expands: 26 legal opening moves, up from 20 in classical chess.
• Notation extension uses Greek letters and zero-based ranks for clarity and engine friendliness.

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🧭 Board Layout (Start Position)

FZFOB is played on a 10×10 board with a classical 8×8 center (Field of Battle) and a surrounding Flanking Zone. The flank columns are labeled θ and χ in tribute to the variant’s roots.

   θ a b c d e f g h χ 
9  * * * * * * * * * *
8  * r n b q k b n r *
7  * p p p p p p p p *
6  * . . . . . . . . *
5  * . . . . . . . . *
4  * . . . . . . . . *
3  * . . . . . . . . *
2  * P P P P P P P P *
1  * R N B Q K B N R *
0  * * * * * * * * * *

• Pieces follow standard algebraic positions inside the central 8×8 Field of Battle (a1–h8).
• The outermost rank and file (0, 9, θ, χ) form the Flanking Zone.
• Knights can move into and out of the Flank. All other pieces must remain entirely within the central field.

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📚 Rules Reference

For a full breakdown of gameplay, board setup, notation, and special mechanics, see the 📖 Rules Directory.

• 🗺️ Board Layout & Notation
• ♞ Knight Movement & Flanking Zone Mechanics (Coming Soon)
• 🧩 FEN/PGN Specification (TBD)

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🧠 Strategic Features

• Flank-first options: Knights can open games by jumping into the Flanking Zone, creating new threats or positioning.
• Enhanced Na3/Nh3 ideas: Previously dubious corner knight moves become gateways to broader maneuvering.
• Simplified rule changes: No modifications to classical piece rules; just one geographic restriction.
• Engine-friendly design: 10×10 board supports clean 0-based indexing, minimal encoding adjustments.

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📜 License

This variant is released under the Creative Commons Zero (CC0) 1.0 license, placing it in the public domain.
You are free to use, remix, adapt, or build upon this idea without asking permission or providing attribution.

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🚧 Future Plans

• 📄 Fully documented rulebook and FEN notation spec
• ♟️ PGN and GUI support examples
• 🤖 Sample engine support or play mode
• 🧪 Playtest scenarios and suggested starting positions

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📫 Feedback / Contributions

Have ideas, diagrams, or even your own fork of this variant? Feel free to open issues or submit PRs.
Let's shape the FZFOB meta together!

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