3. h4 Anti-KID/Gruenfeld

Hi all, I'm curious about 3. h4 against KID/Gruenfeld setups. What sources can I look into to learn more about this? What games are important to know? General concepts? Why h4 is played on move 3 and not delayed for later (e.g., after black has already castled kingside)?

#1
"What sources can I look into to learn more about this?" ++ A data base

"What games are important to know?" ++ Games by strong players.

"General concepts?" ++ The general concept is to question the weakening by ...g6 by immediately threatening to open the h-file for Rh1 with h5.

"Why h4 is played on move 3 and not delayed for later (e.g., after black has already castled kingside)?" ++ That has been there as well: like in The Sämisch Attack against the King's Indian Defence. An early h4 is borrowed from some AlphaZero games.

Right, I was hoping for more specific information. I've already got a couple databases that I'm dipping into, and I already know to look for master games. I'm wondering if there are specific games that were theoretically important in 3. h4 KID/Gruenfeld that I should pay special focus to.

I also already know that the h-pawn is aiming at g6 and threatening to open white's rook. I'm looking for additional information like, how the rest of the pieces are usually arranged, specific tactics that both sides are usually looking for, which pieces usually end up good or bad, or if there are actually several different ways to play 3. h4.

In addition, I'm specifically looking to understand why 3. h4 is a good move to play early, and how those positions tend to differ from the Saemisch Attack, what positions it specifically avoids, and what potential weaknesses there are.

3. h4 is not an opening by itself, it's the inclusion of an early h4 in known defensive systems with g6 Black usually chooses. And Black has many very different systems to choose from : KID, Grünfeld, Benkös, Benonis... So these questions simply cannot be answered in a few lines, if at all. You have to master all the classical setups first and then study what the early h4 will change (it changes a lot of things if Black tries to play an early d5 which is the point). That's actually a lot of work.

Now the reason to play h4 at move 3 is pretty clear. The Grünfeld has such a good theoretical status nowadays and has been so deeply explored that White would prefer to avoid its main lines starting with 3. Nc3 and rather play something fresh.

@4
Has it right.
For comparison, here is what Sveshnikov wrote about an earlier 4...e5 instead of 5...e5:
"By publishing a monograph on the 5...e5 system in 1988, I practically exhausted this variation. Since that time only some details have been developed, without introducing anything particularly new: the evaluations of the main lines have hardly changed. I described everything in such detail, that it became hard playing 5...e5 even against first category players.... I have now played more games with the 4...e5 variation than with 5...e5. And a book on this topic would be twice as thick."
You boldly go where no man has gone before.

Makes sense. It's the difference between committing to a kingside attack (but sidestepping theory) and committing to Nc3 (and probably running into known positions). For example, black doesn't get 3... d5 because after 4. cxd5 Nxd5 5. e4, there's no knight on c3 to exchange, and white has already played h4 which is useful in those types of positions anyway. Maybe white's also not so worried about playing the king to f1 in the future because black has already played g6, and it would be weird for black to play g6 and then put the bishop on c5.

Maybe. The specifics might be different, but maybe that's something along the lines of what people think of when they think of 3. h4.