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# Sonic the Hedgehog Chess Advanced version

```Being both chess variantist and Sonic fan, i could not be unaware of this game. But it's rules were not complete and, in my opinion, it don't bring player in atmosphere of Sonic games deeply enough. Here if piece "uses spindash" it just moves along one line and situations where more than one piece can be captured are quite rare. While in Sonic videogames, after many collisions with robots, springs, flippers, etc, hero changes direction of moving many times and breaks many things. So, i changed mechanism of spindash.
For knight, i used move, suggested by David in comment for original StHC.
Plus, i changed king too. Now it plays role of dr. Eggman. :D```

## Rules

```The only standart piece is pawn.
Ranged pieces (rook, bishop, queen) imitates spindash. If the capturing piece is a ranged piece, instead of displacing the enemy, the capturing piece bounces off, turns 90 degrees either clockwise or counterclockwise (NOT in opposite direction, unlike original StHC) and moves until it reaches another piece or the edge of the board. If the capturing piece reaches a friendly piece or the edge of the board, it stops. If it reaches an enemy piece, it captures it and bounces off again, but only clockwise or counterclockwise, depending on first turn of this move. If it makes another one capture, it turns again (still in same direction, as during first capture). Number of such captures in one move is not limited. If the first capture has one of its potential next directions blocked, by an ally or the edge of the board, the piece must turn in opposite direction. If both sides are blocked, the piece stops right after capture.
Example.
On this diagram R is white rook, Y is any white piece, y is any black piece.

--------
--------
-y-y--y-
--------
--------
------Y-
---R----
--------

Here rook can capture piece on D6. It must chose to bounce clockwise or counterclockwise.
If it bounces counterclockwise, it also captures piece on B6 and stops on B1, before edge of the board.

--------
--------
------y-
--------
--------
------Y-
--------
-R------

If it bounces clockwise, it captures piece on G6 and stops on G4, before friendly piece.

--------
--------
-y------
--------
------R-
------Y-
--------
--------

Knight imitates flight of Tails. This variant was suggested by David in comment for original StHC.
When knight captures, it must move further in same direction, unless if there is friendly piece on destination square or if destination square is out of board.
Example.
N is white knight.

--------
--Y-----
--------
-y--y---
--y-----
N-------
--y-----
----y---

If captures piece on B6, it stops here, being blocked by friendly piece.

--------
--Y-----
--------
-N--y---
--y-----
--------
--y-----
----y---

If it captures piece on C4, it moves further, captures piece on E5 and stops on G6.

--------
--Y-----
------N-
-y------
--------
--------
--y-----
----y---

If it captures piece on C2, it also captures on E1 and stops, as there is no square to move further.

--------
--Y-----
--------
-y--y---
--y-----
--------
--------
----N---

And my own special addition to this game is king dr. Eggman. It represents transformations and breakages of this character's machines. Here king have 3 forms: usual form, with king's usual moves, knight form, with knight's moves and Alibaba form, with moves of Alibaba - jumping as alfil or dababa, exactly 2 squares diagonally, horizontally or vertically:

--------
--------
-x-x-x--
--------
-x-K-x--
--------
-x-x-x--
--------

Player may change his king's form after any move, but not after moving king itself (including castling), not after escaping of check and not after putting opponent's king in check or hiting it.
King may castle in any form.
King don't have to escape from check (though castling limitations are usual), and goal of game is to capture opponent's king. Pawn or king can capture king instantly. But when other pieces hits opponent's king, that king just loses the form he currently in (owner of king must chose next form for it, regardless on his next move). If player's piece is blocked after hiting opponent's king, this piece is lost, but king is damaged anyway.
It's possible to hit king twice in one move. In this case, king loses 2 forms, one is form king currently in, second must be chosen by king's owner. If player hits opponent's king 3 times in one move, king is lost.

Another one optional addition to this game:

rnbqkbnr
pppppppp
--s--s--
--------
--------
--s--s--
PPPPPPPP
RNBQKBNR

Springs on C3, F3, C6 and F6. They can be represented by checkers or players can just remember that they are here (they don't move). They don't affect pawns and kings. Other pieces treats them as opponent's pieces. Springs must'nt be removed from board when pieces leaves thier squares.
For queen and rook, it's not allowed to make "endless moves". Say, rook can't moves from C4 to C6 and bounce clockwise if perimeter of rectangle with springs is empty, because this move will never end.

The game may be played on larger board with more standart pieces and thier compunds, possibly with more springs.

Subvariant, suggested by Charles Gilman: rather than always turning clockwise or counterclockwise in one move, pieces alternates clockwise and counterclockwise turns. If you want to play this variant, you must agree it with your opponent.

My original idea was to make original StHC hexagonal (with pieces from variants of Glinski, McCooey, Shafran, etc.) where ranged pieces turns 120 degrees after each capture, but i decided that similar variant can be played on square-cell board. Of course, hexagonal variant still can be played, but king should be usual, since transforming king would be too strong on hexagonal board. Hexagonal variant can also be played with 60 degrees turns.```

## Notes

`Originally i wanted to add rings to this game, but algorithm of ring losing would be to complicated...`

This 'user submitted' page is a collaboration between the posting user and the Chess Variant Pages. Registered contributors to the Chess Variant Pages have the ability to post their own works, subject to review and editing by the Chess Variant Pages Editorial Staff.

By Daniil Frolov.
Web page created: 2011-04-25. Web page last updated: 2011-04-25﻿