Has anyone ever played chess using a regional chess rule of Riga where knights can only move forward? I just learned about it in this article [http://www.chessbase.com/newsdetail.asp?newsid=2732]

"Tal is born and grew up in the town of Riga, the capital of Latvia. Here, the chess rules have always been a bit different from the rest of the continent. One main difference is that the knights, just like the pawns, can only go forwards, not go back. Throughout his upbringing, Tal has been playing with this rule. And it has been so embedded in his subconscious, that he often forgot that in play and tournaments outside of his native resort, knights were also allowed to move backwards."

sounds pretty interesting

What happens when they reach the other side of the board?

Unfortunately the link I provided is the only reference to this regional rule I was able to find (the reason I ask here)... My guess is that the rule applies only for a certain amount of moves (maybe 30?) or when some material has been exchanged.

Ah well this clears up some confusion for me. I was under the assumption they could promote at the 8th or 9th at any point, and I had a friend who insisted otherwise. I personally enjoy shogi because of its attacking capabilities. An attack can materialize out of nowhere and setting up a defense is usually only considered prudent during the opening. 

The part about Shogi is perfectly true - the part about Riga is as true as the stories about drop-bears in the Australian outback. 

I want to trust chessbase as a legitimate source of information... but I find it questionable being unable to find another reference to this rule on the web...

Well, I reason it like this. In shogi the rule works because horses can be promoted to a piece which does have the ability to move backwards (though it's not good at it) and in any case shogi pieces, when captured, become available for the opponent to drop on the board in lieu of a move, so horses can turn up anywhere. Since neither of these is ever true in chess, how would a forwards-only knight ever be useful? The author was making a joke, that's all.

Sounds like a prank call I got once.

If you read the annotations of the game, you see Shirov in both games retreat one of his knights. In the first game against Kortschnoi on move 12, in his game against Polgar at move 8.

The writer knows that. I think Shirov meant to say that they were taught to play adventurous and that knights are the first pieces to start an attack with. The writer exaggerates it a little to bring his point home.

Póg mo thóin Sasanach.

(Apologies for any bad grammar there.)