Thoughtwave
by Derick Green
(first published in the Games and Puzzzles Journal issue 14)

Thoughtwave first appeared in the mid-1970s, and is a two-player abstract path-making game.
The inventor was Dr Eric Solomon (See update in footnote below), and the game was first produced by Intellect Games.

The game is easy to learn but has considerable depth in its tactical play, a draw is almost impossible and the following simple handicap system allows players of different strengths to compete on equal terms. The stronger player simply gives the weaker player 1, 2 or 3 of his tiles.

A thoughtwave set is easy to make, a 10×10 board is needed and two sets of 24 tiles. The tiles and the squares on the board need to be the same size (1 inch or 2½ centimetres will do). The object of the game is to be the first player to connect opposite sides of the board with a 'thoughtwave'. Say player A North to South, and player B West to East. The squares connected do not need to be directly opposite each other.

The 'thoughtwave' with which the players attempt to connect opposite sides of the board is made from up to 24 tiles of five different types (Figure 1). In the original design the 'waves' were more rounded. A tile, once placed on the board, belongs to neither player and may be used by either player as part of their respective 'thoughtwaves'.

The most numerous tile is the Bend (10 tiles each) which connects two adjacent sides of a square. Bends are specially useful in the first few moves of a game to mark out potential thoughtwaves. The T-piece (6 tiles each) connects three sides and the Cross (2 tiles each) connects four sides. Both become increasingly important as the game progresses.

The Straights (5 tiles each) connect two opposite sides and are useful as blockers. In Figure 2(a), A has a North to South Straight on e4 which is blocked by B's West to East Straight on e2, so A is forced to divert and B has made a counter-threat.

Finally, the Terminator piece (1 tile each) connects one side only and should be used carefully. A player must keep his options open by laying down alternative routes. In Figure 2(b) A's route at b3 and c3 is blocked by B playing his Terminator at c2. However, A has another route via a3 and a T-piece placed at a2, as shown in white, would guarantee A connecting to the southern edge of the board.

Thoughtwave is played in turns, with each player placing one tile in any empty square on the board. A tile once placed cannot be moved unless found to be illegally placed. In this event the guilty player removes his tile and misses one turn. A tile placed next to another must have connecting thoughtwaves, similarly blank edges must touch blank edges.

Two important facts to remember are that blank edges are just as important as connecting edges and too many T-pieces should not be used too early in the game.

For recording the game I have used a notation system using the four compass points and the square coordinates. For example in Figure 2(a) the Straight at e4 would be recorded as NSe4. The following short game is between two new players. Note that at the end of the game, Figure 2(c), squares d3 and f5 are useless as if either player places a tile into one square their opponent plays into the other and wins.

Illustrative Game: Player A (N-S), Player B (W-E)
1. NSe6NEe52. NWf4SWEg53. NEd10SEh6
4. NSEe9WEj65. NWe3WEc36. NSWd2NWEa3
7. NSe7NEb28. NSd1SEf69. SEe4NWh5
10.SWe10SWE b311. NSe8WEi612. NSEg3resigns.

(The tile patterns in Figure 2(c) have been simplified to make the drawing easier to do.)

Update The inventor, Dr Eric Solomon now has his own site: ericsolomon.co.uk. He wrote to the editor, George Jelliss, on 10 February 2004 after seeing Derick Green's account of his game and asked for some details to be corrected. He noted that there are a number of other implementations of Thoughtwave on the web, and recommended that by Thad Frogley, which was at http://www.geocities.com/TimesSquare/Stadium/2652/main.htm but all geocities sites were discontinued by the Yahoos.