The five-in-a-row is won when there is a straight line of five or more stones, horizontal, vertical or diagonal.

The game starts with the board empty, crosses making the first move. Each player takes turns placing his or her circles or crosses in empty cells on the board.

Requirements:
Requires any Pocket PC compatible device with: Windows Mobile 2003 or higher OS
- or -
Any earlier system with the .Net Compact Framework installed.

SOURCE

http://www.rifcomobile.com/pocketmoku

Reviews:

***** [Apr 11, 2009] by dsf3g using HTC Touch
It's been mathematically proven that a perfect Gomoku player who moves first will always win the match. The challenge to creating a good Gomoku computer game, then, is to implement an imperfect strategy for the computer player that is still challenging for the typical human opponent. This implementation does that well. Beating the computer is not impossible, but it is challenging enough that your PDA/Phone will provide you with a nice enjoyable 5 minute diversion. Highly recommended.