Hopgi

By

Peter Aronson

Introduction

Board and Setup

	+---+---+---+---+---+---+---+ 7 |:r:| p |:::| |:::| |:/:| +---+---+---+---+---+---+---+ 6 | w |:p:| |:::| |:/:| | +---+---+---+---+---+---+---+ 5 | p |:::| |:/:| |:::| +---+---+---+---+---+---+---+ 4 | f |:p:| |:/:| |:::| | +---+---+---+---+---+---+---+ 3 |:b:| p |:/:| |:::| |:::| +---+---#---+---+---+---+---+ 2 | P |:P:| P |:P:| P | +---+---+---+---+---+ 1 |:B:| F | | W |:R:| +---+---+ +---+---+ a b c d e f g
Black Wazir King (w): a6 Ferz King (f): a4 Rook (r): a7, 1 in hand Bishop (b): a3, 1 in hand Pawn (p): b3, b4, b5, b6, b7, 1 in hand	White Wazir King (W): f1 Ferz King (F): d1 Rook (R): g1, 1 in hand Bishop (B): c1, 1 in hand Pawn (P): c2, d2, e2, f2, g2, 1 in hand

Board notes:

1. The corner connecting squares b3 and c2 (marked with a '#' in the ASCII diagram) is blocked, and may not be moved through.
2. Those squares marked with 'x's or slashes (c3, d4, e5, f6 and g7) above divide the board into two zones, the zone on the right being where Pawns move up and down, and the zone on the left being where Pawns move left and right. Marked squares are in both zones. See below for more detail.

General Rules

• Like in Chessgi, any pieces a player captures become their color, and are put in hand. Like in Shogi,but unlike in Chessgi, promoted pieces are "unpromoted" when placed in hand. In hand pieces may be dropped on empty squares on the board on later turns as a move. Unlike in Chessgi, there are no restrictions on Pawn drops. The royal pieces (Wazir King and Ferz King) are not placed in hand when captured, but removed from the game.
• All pieces other than the Kings promote when moved into one of the four squares that enemy pieces other than Pawns started on. Pieces dropped onto these squares do not promote when dropped, but promote when they move from one of these squares. Pawns promote to Guardians, Bishops to Dragon Horses, and Rooks to Dragon Kings.
• The King is replaced by a a Ferz King and a Wazir King. When one of them is moved, then the other one must also be moved in the same turn if at all possible. To win, you must capture (not mate) both of your opponent's Kings. It is perfectly legal to move a King into an attacked square.

The Moves of the Pieces

	+---+---+---+---+---+---+---+ 7 |:::| |:::| |:::| |:/:| +---+---+---+---+---+---+---+ 6 | |:::| |:::| |:/:| | +---+---+---+---+---+---+---+ 5 | |:::| |:/:| |:::| +---+---+---+---+---+---+---+ 4 | |:::| |:/:| |:*:| | +---+---+---+---+---+---+---+ 3 |:::| |:/:| |:p:| |:P:| +---+---#---+---+---+---+---+ 2 | |:::| |:p:| W | +---+---+---+---+---+ 1 |:::| | | |:b:| +---+---+ +---+---+ a b c d e f g

The White Wazir King on g2 may either leap over the Black Pawn on f2 to capture the Pawn on e3, or it may leap over the White Pawn on g3 to land in the empty square at f4 (marked with a blue circle or a '*'). Note that a piece on c1 could not leap to b3 even if there was a piece on c2, as the diagonal portion of the move would be illegal as c2 does not connect to b3 (see board note 1 above).

The pieces:

• The Wazir King moves one step orthogonally (up, down, left or right). If a Wazir King is moved, and the moving player still has a Ferz King, the Ferz King must be moved as well if any legal move is available.
• The Ferz King moves one step diagonally. If a Ferz King is moved, and the moving player still has a Wazir King, the Wazir King must be moved as well if any legal move is available.
• The Rook moves as a standard FIDE Rook, except that is restricted to moving no more than three squares at a time. It promotes to a Dragon King, which adds the ability to move one square diagonally. (The Dragon King, without the three-square movement restriction, is from Shogi, where it is the promoted form of the Rook.)
• The Bishop moves as a standard FIDE Bishop, except that is restricted to moving no more than three squares at a time. It promotes to a Dragon Horse, which adds the ability to move one square orthogonally. (The Dragon Horse, without the three square movement restriction, is from Shogi, where it is the promoted form of the Bishop.)
• The Pawn moves like a Berolina Pawn -- capturing one step directly forward, or moving one step diagonally forward without capturing -- but without the initial doublestep or en passant capture. However, the concept of "forward" is not entirely simple for Pawns on the Hopgi board.

  Forward is left-to-right for Black and bottom-to-top for White. However, forward changes when the Pawns reach the diagonal line dividing the board (which is on squares c3, d4, e5, f6 and g7), becoming top-to-bottom for Black and right-to-left for White. Pawns actually on the line may use either forward direction.

  So, for White, some possible moves for Pawns are:

  +---+---+---+---+---+---+---+ 7 |:::| + |:::| |:+:| x |:+:| +---+---+---+---+---+---+---+ 6 | |:x:| P |:::| x |:P:| | +---+---+---+---+---+---+---+ 5 | + |:::| |:+:| |:::| +---+---+---+---+---+---+---+ 4 | |:::| |:/:| |:::| | +---+---+---+---+---+---+---+ 3 |:::| |:/:| |:+:| x |:+:| +---+---#---+---+---+---+---+ 2 | |:::| |:P:| | +---+---+---+---+---+ 1 |:::| | | |:::| +---+---+ +---+---+ a b c d e f g

  Where red circles or 'x's indicate squares where only capture moves may be made, and green circles or '+'s indicate squares where only non-capturing moves may be made. So for the White Pawn on f2, forward is up, for the White Pawn on b6, forward is to the left, and for the White Pawn on f6, since it is on the dividing line, forward is either up or to the left.

  For Black, the equivalent moves for Pawns are shown here:

  +---+---+---+---+---+---+---+ 7 |:::| |:+:| |:::| |:+:| +---+---+---+---+---+---+---+ 6 | |:p:| x |:::| |:p:| x | +---+---+---+---+---+---+---+ 5 | |:+:| |:+:| x |:+:| +---+---+---+---+---+---+---+ 4 | |:::| |:/:| |:::| | +---+---+---+---+---+---+---+ 3 |:::| |:/:| |:::| p |:::| +---+---#---+---+---+---+---+ 2 | |:::| + |:x:| + | +---+---+---+---+---+ 1 |:::| | | |:::| +---+---+ +---+---+ a b c d e f g

  Pawns promote to Guardians, which are omni-directional Berolina Pawns, able to move one step in any diagonal direction without capturing, and to capture by moving one step in any orthogonal direction. (Guardians were introduced by Fergus Duniho in Interdependent Chess.)

Notes and Comments

The initial inspiration for this game came from Gavin King's game of Fleap, with its use of Equihoppers. And I thought: if he can give the Equihopper a variant to call its own, why can't I do that with the Mao-hopper? This made the game design resemble one of those variants where all pieces can move like Knights in addition to their regular moves, such as Cavalry Chess or Cavalier Chess. This was fine, as I've always liked that genre of variants. Fortunately given the small size of the board, the additional power supplied by a Maohopper move is considerably less than that added by a Knight's move.

Then came the usual N-square contest activity of sketching boards in my spare moments. For some reason, I started on a four-player cross-shaped board -- it required too many spaces, but with two sides deleted I ended up with the current Hopgi board. This put the two sides at right angles, which I thought was sort of interesting, and reminiscent of four-player variants with the partners across from each other. The Pawn change of direction was inspired by a similar rule in the four-player variant Chessapeak Challenge, although that game does not use Berolina Pawns. The blockage between squares c2 and b3 was a last minute tweak to prevent pieces from having first turn captures, which I considered esthetically displeasing.

The Chessgi/Shogi-derived rules for capture and drop were added as they seem to work well on small boards -- small Shogi variants are considered very playable. Making all pieces short range increased the Shogi-like feel, and made drops a bit less powerful.

The last unusual part of the game, the limited but linked Kings, is actually something I've been kicking around for a while. A standard FIDE King plus Mao-Hopper seemed a bit too strong, but reduced Kings seemed too weak. A pair of weak Kings, however, worked better, particularly since you can sacrifice one (say, to gain tempo when you're being chased around the board by your opponent's drops) and still win. The linked move also makes it harder for a player to hunker down behind fortresses of mutually defending pieces.

I considered using the King capture rules from Fergus Duniho's Three Player Hex Shogi 91 where you have to collect all Kings to win and captured Kings went in hand, but you could not drop any other pieces until you dropped all captured Kings. However, I was afraid it would draw out the game too much. (It doesn't have that effect in Fergus' game, but it plays very differently than Hopgi.)

This game is a thematic relative to my game Mulligan Stew Chess, which was a non-competing entry in the The contest to design a chess variant on 42 squares. Like Mulligan Stew Chess, Hopgi contains a variety of apparently disparate elements that I felt worked together well (this is rather how I make soup too, actually). In both cases there was one common theme: fluidity. I was looking for game elements that would prevent static positions. In the case of Mulligan Stew Chess it was teleporting pieces, switching pieces, leaping Pawns and double moves. In the case of Hopgi, the drops, the Mao-hopper moves, the fairly large amount of material (allowing exchanges to open positions) and the linked-Kings all result in a game where board positions should not get locked up.

Thanks to Tony Quintanilla for playtesting and comments.

Computer Play

I have written an implementation of Hopgi for Zillions of Games. You can download it here:
• hopgi.zip

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Written by Peter Aronson.

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WWW page created: April 11th, 2003.

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