ST. LOUIS – Wesley So was unpacking his bags at a stately hotel in St. Louis where the grandmaster from Minnetonka would spend the next 14 days trying to prove that he's the best chess player in the United States.

Then the room phone rang. He had guests in the lobby.

As he stepped off the elevator, there was his estranged mother, who had arrived without notice from Toronto to confront him about dropping out of college last year.

The surprise encounter began a series of contentious meetings over a handful of days — and as the family drama unfolded, Wesley So unraveled.

He became afraid to walk through the hotel lobby for fear that his mother would accost him. Wary of walking the two blocks from the hotel to the chess tournament site, he would arrive at the playing hall rattled. Over the board, he missed key moves and the losses mounted, dashing his hopes of winning the U.S. Chess Championship.

In a larger sense, a battle over the best interests of a 21-year-old with one of the world's most amazing minds was playing out within the narrow confines of a family spat and against the backdrop of global chess politics.

And in this game, it seems, the grandmaster is the pawn.

When So's forfeit for a rule violation on Friday brought the back story of his mother's visit to the fore, the combined events shocked everyone involved in the tournament and horrified Grandmaster Yasser Seirawan, a four-time U.S. champion who is providing live commentary on the event.

"I just cannot understand why anybody would do that," Seirawan said Saturday about reports of the mother's confrontation. "I thought that was an incredibly cruel thing to do, and for such a sweet person like Wesley, I can imagine how upsetting he found that."

The chess community, global yet relatively small and insular, was aware for some time that a drama was playing out in So's personal life, but the details were unknown, said Grandmaster Alejandro Ramirez, another commentator at the U.S. Chess Championship.

"It all came crashing down in this tournament … and I'm still not sure what's going on … and it's not my business to know … but it's obvious that he has to fix a lot of things in his life before he decides to move forward," Ramirez said. "It's amazing that he's gotten [as] far as he has even with all these problems."

A child chess prodigy, So broke world age records for achievements and became a grandmaster at 14, at the time the seventh youngest in history. He was the pride of the Philippines, where chess holds an honored status. When So was in his midteens, his parents, along with his two sisters, moved to Canada. So stayed behind.

The family he lives with now in Minnetonka describes So — and not in a critical way — as being one-dimensional. He played chess, and that was pretty much it. Renato Kabigting, the father in the Minnetonka family, likens So to kids who are reared to become gymnasts from the time they are toddlers, and exposed to little else.

So arrived in the United States in August 2012 on a full-ride chess scholarship at Webster University in suburban St. Louis, where the chess team is stacked with grandmasters. There is a fierce rivalry among a select few colleges, and they recruit globally, importing teen grandmasters.

The chess program at Webster is run by Grandmaster Susan Polgar and her husband, Paul Truong. She is a former Women's World Champion, and together they are controversial figures in the chess universe. In the current issue of New in Chess, a Dutch magazine, they are ridiculed for what the author describes as fantastical claims.

Polgar and Truong were elected to the U.S. Chess Federation's executive board in 2007 in what turned out to be a tainted election. They were pushed out amid a series of lawsuits and countersuits.

But under their tutelage at Webster, So flourished, rising to become the No. 10 player in the world. During that time, as the chess world took note of So's growing talent, the battle over his future began.

It started on the international level. So was still a member of the Philippine Chess Federation, but he wanted to switch to the U.S. because he felt he'd get more recognition and opportunities. Federation allegiance is key, because national chess teams compete in Olympic-style competitions, and having a top-10 player is an obvious bonus.

As an example of what's at stake, the New York Times recently reported that the world's No. 2 player, Fabiano Caruana, said that he was offered tens of thousands of dollars by a wealthy individual to switch to the U.S. from Italy. Caruana, born in Miami, holds dual citizenship in the two countries.

In So's case, Philippine officials refused to release him, so he took a stand and said he wouldn't play for the country in last August's chess Olympiad. Eventually, Philippine officials relented, and So paid a fee of about $5,000 to switch to the U.S., delighting chess fans here. Back in the Philippines, a senator asked for a government investigation over how the country lost So.

Chess career

At the same time So switched federations, disagreement within his family about his future spilled into public view.

After two years at Webster, So was struggling to balance the demands of college with his aspiration to play in more elite international tournaments so he could test himself against the very best. He chose the tournament path.

On short notice, he dropped out of Webster last October, dealing a blow to Polgar and Truong's chess team, where he was their best player, or "board one" in chess parlance. It happened just a few months before one of the most important collegiate chess tournaments.

The decision to drop out also upset his mother in Canada.

Eleanor "Leny" So gave an interview to the website Chessdom in December, in which she criticized her son for quitting school. "I have a negative feeling as a mother that this is a very huge mistake on Wesley. It hurts me terribly," she said.

She also was fulsome in her praise for Polgar and Truong, saying "they took Wesley in and treated him like their own son." She credited them for her son's leap in world chess rankings and for transforming him from "a talented boy … [to] an accomplished man."

Susan Polgar reposted the full interview on her website.

What wasn't said at the time, but is now by So and his Minnetonka family, is that he was growing unhappy and feeling isolated at Webster. Those issues were factors in his decision to drop out, they said.

So turned to the Minnetonka couple of Lotis Key and Renato Kabigting, fellow Filipinos whom he'd met at a private dinner in August 2013, while playing in a Twin Cities tournament. They had remained in close contact, with So visiting them during the 2013 Christmas break, and the couple traveling to Webster to spend time with him in October 2014. Later that month, he moved in with them and their young adult daughter. He had a new family.

So calls Key "mom," though Key often adds "foster" for clarification.

Key is a former star of Asian films and is now a freelance writer and vice president of the Minnesota Christian Writers Guild. Kabigting, an amateur chess enthusiast, works in ground services for Delta Air Lines.

Key and Kabigting say Truong, the Webster chess coach, was too controlling of So, and he repeats the same charge against them. What's clear is that there was a falling out and Key believes Truong, still upset over losing So from Webster, played a role in the mother's untimely visit. Truong denies it, though he acknowledges being in e-mail contact with So's mother a month before the tournament began.

Seirawan said he doubts Truong was involved with the intrigue over the mother's visit.

Whatever the case, experts say it clearly affected So's performance in the national championship, where he'd lost three games before his forfeit. While he didn't impress anyone with his play, he was winning fans for how he handled defeat. Except for a veiled reference in one interview about some people wanting top players to fail, he remained upbeat and funny in his postgame interviews. That prompted one chess fan to tweet to the commentators that So seemed "like a bloody lovely chap."

Now the question becomes whether a short break and a lot of distance will return So to form as a player. In a matter of days he begins his next elite tournament, the Vugar Gashimov Memorial in Azerbaijan, with a field that includes five other world top-10s, including the world champion.

Seirawan sees it as a blessing for So. He said So won't be spending weeks or months dwelling on his poor performance. Plus, he'll be safely on "the other side of the world and nobody is going to be bothering him."

On Saturday, So appeared to already take a step in that direction. He defeated the defending U.S. champion in decisive fashion.

Dennis J. McGrath • 612-673-4293