List of Games‎ > ‎


The standard or tournament Y board

Alternate Names

No. of Players

The game of Y may be the positional board game with the greatest number of boards used for playing it. The one shown above, however, is considered the tournament Y board and has become the most common for play of Y.

Y was invented by Charles Titus and Craige Schensted (later known as Ea Ea) at the University of Michigan around 1953. It came about as a derivation of the game of
 Hex.  Y was also independently discovered by Claude Shannon, known for his Information Theory. Shannon also invented a closely related game called the Shannon Switching Game, discussed here as a variation of Hex.  Titus and Schensted significantly advanced the complexity of the game of Y when they realized in 1969 that the playing cells need not be made entirely of hexagons. Utilizing what they called the Mudcrack Principle they greatly developed the design and balance of the Y board over time, eventually arriving at the Tournament Y board used for the game today. A huge plethora of game boards for play of Y came about as they researched this concept and their results can be seen in their book Mudcrack Y and Poly-Y published in 1975. Y was also a sort of stepping stone in the evolution of Hex into the gradually more complex games of Poly-Y, Star and *Star, all invented by Schensted (Ea Ea). 

The objective of both players is to create a "Y" on the board, a continuous line of counters of their color that touch and bridge all three edges of the board. Like Hex, it is impossible for the game to end in a draw. Note that a "Y" formation, as they are called, commonly resemble the letter Y turned at any angle and thus the name, but it is also common that the winning formation will not look anything at all like the letter Y.

Alternate turns entail the placement of a single friendly counter at any vacant position on the board. Once placed, counters are not moved, captured, or removed.


This triangular hex grid was typical for play of Y prior to 1969.
Numerous boards have been used to play this game.  Prior to 1969, this game was always played on a simple triangular grid composed entirely of hexagons.  The rules were the same, but a board of all regular hexagons greatly changes the dynamic of the game.  Any size variation of such a board will work to play this precursory game, but the same problem always arises: the center position is too powerful.  The pie rule could, of course, be utilized, but this simply diverts the problem.  The game played on one of these simple boards lacks depth that arises from later developments to the game.

Larger and Smaller Boards (where counters are still played at the vertices)

Larger and Smaller Boards (where counters are played in the cells)

Mudcrack Y
The Mudcrack Principle, as it came to be called, was first realized by Craige Schensted and Charles Titus around 1969 and was discussed in their book Mudcrack Y & Poly-Y  (1970, 1975).  When mud dries out and cracks it forms patterns (which also can be seen in drying paint or ceramic glaze).  The Mudcrack Principle states that any such pattern could be used as a Y Board if three edges are added.  Several such examples are given in their book and shown here:
Per the Mudcrack Principle, any of the above triangles could be used as Y Board

Master Y, mentioned in Mudcrack Y & Poly-Y (1), allows a player to place two stones on every turn with the exception of the first move, when only one is played.  

Holey Y, also mentioned in Mudcrack Y & Poly-Y (1), utilizes boards with holes of unplayable areas in the central regions. 
Holey-Y Boards from Mudcrack Y & Poly-Y (1).

Quadrant Y by Cameron Browne, author of Connection Games (2), has a triangular board with an an odd number of hexagons per side that is split into four equilateral triangles. The triangles overlap, indicated by darker shading in the board shown below.  Each of the four smaller triangles hosts a smaller game of Y, with one larger game taking place on the entire board. The goal is to win the majority of these five sub-games.

Caeth Y

                            1- *
                           2- / \
                          3- *-.-*
                         4- / \ / \
                        5- *-.-*-.-*
                       6- / \ / \ / \
                      7- *-.-*-.-*-.-*
                     8- / \ / \ / \ / \
                    9- *-.-*-.-*-.-*-.-*
                  10- / \ / \ / \ / \ / \
                 11- *-.-*-.-*-.-*-.-*-.-*
                12- / \ / \ / \ / \ / \ / \
               13- *-.-*-.-*-.-*-.-*-.-*-.-*
              14- / \ / \ / \ / \ / \ / \ / \
             15- *-.-*-.-*-.-*-.-*-.-*-.-*-.-*
            16- / \ / \ / \ / \ / \ / \ / \ / \
           17- *-.-*-.-*-.-*-.-*-.-*-.-*-.-*-.-*
                \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \
                 A B C D E F G H I J K L M N O P Q
Players alternate turns, capturing an edge between two vertices on each of their turns. When a player controls half or more of the edges leading into a vertex, they gain control of that vertex. (Specifically in Caeth Y: control of one edge into a corner vertex, two edges into a side vertex, or three edges into a centre vertex are enough for control.) As in Y, the goal is to make a connected chain of vertices that touches all three sides of the board; the three corners count as members of both sides to which they are adjacent. Note that the connected chain is a chain of vertices, not of edges. The second player may utilize the swap rule if they so desire.

  1. Schensted, Craige and Charles Titus.  Mudcrack Y & Poly-Y.  NEO Press, 1975.  ISBN 0-911014-23-3
  2. Browne, Cameron.  Connection Games: Variations on a Theme.  A K Peters/CRC Press, 2005.  ISBN 978-1568812243