Tom Kerrigan got hooked on computer chess as a 13-year-old growing up in Fort Collins, Colo. A friend of his got the Chessmaster game for the PC, and Kerrigan tried to make an illegal copy for himself.

“I tried to pirate the game and it had some kind of copy protection. I was into programming at the time, and I thought how hard could it be to write a chess game?” Kerrigan said. “Ever since then I got really interested in that.”

The amateur programmer kept tinkering with computer chess through high school and college, though he didn’t have as much time for it after joining Microsoft out of college in 2001. He worked for the software giant for four years, mostly on Office user interface.

After a brief stint at a startup company called MindTouch in 2006, Kerrigan took some time off, backpacking in Europe and Asia. Later, as he was contemplating what to do next, he started thinking about a chess game for the iPhone — Apple’s popular mobile device — but initially thought he was too late.

“I didn’t have the idea to work on iPhone apps (applications) because I thought the market would be flooded and there would be too much competition,” Kerrigan said. But, he said, “I looked at iTunes and it turned out there wasn’t much out there. I saw an opportunity.”
He bought a Mac and an iPhone, did research, registered as a developer with the Apple App Store, and started coding.

The result was a game called tChess. The first version of the game, called tChess Pro for chess enthusiasts, went into the Apple App Store on Nov. 6. It sells for $8. A second version for casual players called tChess Lite, which sells for $1, got released Nov. 15.

For Kerrigan, watching the progress of the tChess games has been an exhilarating and at times nail-biting roller-coaster ride.
A friend alerted him when tChess Lite, the $1 game, made it into the Apple App Store’s top 100 paid applications. The game steadily advanced through the rankings, peaking at No. 12 “for a couple hours,” according to Kerrigan.

But Kerrigan recently saw the game plummet into the high 90s in the rankings, an event he attributed to a temporary bug in the iTunes search feature. Since then, tChess Lite has been “clawing its way back up the list,” he said. (Earlier this week, it was in the No. 77 position, but today is in 100th place). An Apple spokesman could not immediately be reached for comment.

Kerrigan admits to having second thoughts about the iPhone after his game almost fell off the charts.

“It was very frustrating,” he said. “There was a question of does it matter whether or not I improve the game at all.”

But Kerrigan, who just turned 30 and lives in a one-bedroom apartment in Redmond, says he’s making enough money to support himself with the iPhone games. He declined to specify his income from the iPhone, but said he’s sold “tens of thousands” of applications on the device. Apple takes a 30 percent cut of all sales.

“I could live off of my income,” Kerrigan said. “I was going to look for a job but I’m not now because I’m going to pursue this for financial reasons.”

There are a number of chess games available for the iPhone. Kerrigan is confident that his is better, but he keeps an eye on the competition, including a new iPhone chess application called Deep Green.

While Kerrigan says he doesn’t need a day job right now, he cautions others against chucking it all to develop applications for the iPhone. Chess is somewhat unique in that it has a built-in following, whereas other games require a lot of exposure to get noticed, he said.

“If you’re somebody who wants to quit their job and start writing iPhone apps, it might be a different situation,” he said. “You might come up with a great game, but no one really knows about it and it doesn’t catch on.”