BIEL, Switzerland — GM Wesley So of the Philippines played cautiously with white and settled for a draw with GM Parimarjan Negi of India in the fourth round of the 2010 Biel Young Grandmasters chess championship here Thursday.

So and Negi, the two youngest participants in the 10-player, category-17 tournament, agreed to split the point after 28 moves of the Queen’s Gambit Declined.

The draw, however, was enough for So to keep the solo lead in the nine-round closed tournament with three points on two wins and two draws.

The 16-year-old Filipino champion, who won both his matches with the black pieces, is still half a point ahead of second seed GM Evgeny Tomashevsky of Russia, third seed GM Fabiano Caruna of Italy and sixth seed Dmitry Andreikin of Russia.

Tomashevsky and Caruana battled each other to a draw, while Andreikin subdued GM David Howell of England in the other notable fourth-round encounters to stay within striking distance of the fourth-seeded Filipino campaigner from Bacoor, Cavite.

Negi, who became the world’s second youngest GM of all-time at 13 years, three months and 22 days, finally ended a three-game losing skid with the draw with So. The 17-year-old former world junior champion from New Delhi lost his first three matches.