THE conventional wisdom says a player reaches the peak of his or her ability around age 30.

The conventional wisdom also says you can’t come back to your former strength after several years away from the board.

For Gata Kamsky, the current Corus international at Wijk ann Zee in the Netherlands is a test of which wisdom is wiser.

Kamsky famously defected from the Soviet Union during a New York Open when he was 15, became U.S. Champion two years later and was among the world’s top five players within a few years.

But after losing a world chess federation (FIDE) world championship match to Anatoly Karpov, he left chess, graduated from Brooklyn College, obtained a law degree, married and had a son.

Just as mysterious as his disappearance was his return to chess in 2004, 10 years after his last USCF-rated game. His play seemed rusty and his knowledge of opening theory outdated.

But Kamsky got back into form in 2005, reached No. 25 on the world rating list and qualified along with 15 other strong grandmasters for the candidates stage of FIDE’s next world championship cycle.

Now 31, his biggest challenge comes at Wijk aan Zee, his first top-notch round-robin tournament in more than a decade. The going is rough: He scored one victory and four losses in his first five games.