## Help For the Game Of yXy

### Introduction

Welcome to the network yXy server. The challenge command is described here, and move syntax is descirbe below. Other commands are the same for all pbmserv games.

yxy challenge [-size=number] userid1 userid2

Start a new game between userid1 and userid2

The -size parameter sets the overall board size. This must be in the range 2..26 (the default being 11).

### Rules

yXy consists of the three connection games played simultaneously: one Hex game and two Y subgames.

The Hex game is played on the full board according to the standard Hex rules: Vert strives to make a chain of pieces between the top and bottom sides while Horz strives to make a chain of pieces between the left and right sides.

The Y subgames are played in the two triangular board halves according to the standard Y rules: players strive to connect all three sides of each triangle with a chain of their pieces. The column along the short diagonal (marked ',') is shared by both Y subgames.

The game of yXy is won by the player who wins at least two of the three component games. Exactly one player must win.

yXy is an elegant combination of the two fundamental connection games Hex and Y. It is like a non-recursive and non-homogenous blend of Quadrant Hex and Quadrant Y.

### Example Game

The following example shows a game won by Vert, who has won the Hex game plus one of the Y subgames. Horz has won the other Y subgame.

a b c d e f g h i j k

1   . . . . . h . . v . ,   1
2   . . . . h . . . v , .   2
3   . . . h . . . . v . .   3
4   h h h . . . . , v . .   4
5   . . h . . . , . v . .   5
6   . . h . . , . . v . .   6
7   . . h . , . . . v v v   7
8   . . h , . . . v . . .   8
9   . . h . . . v . . . .   9
10   . , h . . . v . . . .   10
11   , . h . . . v . . . .   11

a b c d e f g h i j k

### Syntax

Vert moves first. The move syntax is:

`  F6     Place a piece at coordinate F6, which must be empty.`
```  swap   Horz may elect to swap Vert's opening move as their first play.
This ensures that Vert does not start with too strong an opening move.```

### History

yXy was invented by Patrick Mouchet in 2007.

Implementation and help file by Cameron Browne, July 2007.