With a win in the seventh round Wednesday, an elite Twin Cities chess player has kept alive his hopes of winning the national championship.

Grandmaster Wesley So narrowed the gap between himself and first place by winning his fourth game of the U.S. Chess Championship tournament in St. Louis.

So now trails the two co-leaders by only a half point with four rounds to play.

Uncharacteristically, So had lost two of his first six games and appeared to be in danger of falling out of contention. He acknowledged Wednesday that "it's clear that I'm not on good form in this tournament."

But the world No. 8 player has made up for his two losses by winning four of his other five games. That has kept him within striking distance as his chief rivals have had fewer wins and more draws than him. (Players get one point for a win, a half point for a draw and nothing for a loss.)

In Wednesday's game, So steered a lifeless looking game to a victory by suddenly manufacturing threats. With his two bishops occupying key diagonals, raking across an uncluttered board toward his opponent's king, he ratcheted up the pressure until his opponent, Grandmaster Alexander Onischuk, went astray.

Looking ahead to the final games, So said he as to "avoid self-destructing -- I mean ignore the critics. As you know, in the chess world there are some people who want to see you fail, who want to see the top players fail. You just have to ignore that fact and focus on your opponents."

So still has a particularly difficult opponent in his remaining pairings -- defending U.S. champ Gata Kamsky.

But working in So's favor is that the two leaders, Grandmasters Hikaru Nakamura and Ray Robson will have to play each other on Saturday in the penultimate round. That could give So a chance to gain ground on one of them -- or both, if they draw and So wins that day.

In Thursday's round at the Chess Club and Scholastic Center of St. Louis, So plays Grandmaster Conrad Holt of Wichita, Kan., the lowest-rater player in the 12-player field.

Dennis J. McGrath -- 612-673-4293