What is the hardest variant according to you (and taking which side)?

Horde is very hard, hats off to @RayHolt, and @hordingholdor(same person) on becoming champions in Horde. Antichess is somewhat complicated, sacrificing your pieces without any reason, and so are bughouse and crazyhouse which I really find a lot of crazy bugs. And also playing Black in RK, is a real fun, if you just go on playing the same moves as White (until and unless White is an experienced RK chess player). But the hardest variant is the Standard or the Normal variant.

I just don't like King of The Hill and Racing kings... It’s even worse when you have the black pieces coz in these 2 white has a lot of advantage.

It's not the matter whether it is hard or easy. If we learn anything is easy. If we won't everything is hard.
Just the matter of practice and interest.

@Mohith797 said in #23:

It's not the matter whether it is hard or easy. If we learn anything is easy. If we won't everything is hard.
Just the matter of practice and interest.
Says the guy who doesn’t play crazyhouse, chess960 with me when I challenge.

@Kumbaya_Haha Haha yeah I didn't learn Crazyhouse and Chess960, so I don't play. If I learn I'll win in that too as I win in other variants with you.

@Abigail-III said in #6:

anti-chess should use the chess 960 rules to set up the game

I totally agree

I like my own 9x9 chess but it's not caught on yet.

Crazyhouse and three-check baffle me. Giveaway (loser's) I played a lot as a kid (intentionally or otherwise).

@SamannOyB said in #21:

But the hardest variant is the Standard or the Normal variant.

What???O!

Well, when you analyze a crazy house position with stockfish, then you see what is +2.0 advantage on the initial position. It needs thinking.

Then comes Chess960, which is easier for some players to avoid opening preparation, and harder for some for not being able to play openings. The greatest disadvantage of Chess960 is blundering on openings, especially when the bishops are on long diagonals like a1. b1, g1, or h1.

Three-check (no one mentioned that here) is a variant in which one has to become very careful, like not to get three-checked forcefully. If one blunders a forced three-check line, then the opponent can easily win. Like 1. e4 1...e5 2. Bc4 2...Nc6?? 3. Bxf7+ and you have to play Ke7 or you will get mated by 3...Kxf7 4. Qf3+ 4...K(anywhere) 5. Qf7# or 4...Nf6 5. Qxf6# [# means three-checked].

KOTH is a variant where people blunder pieces to move the king to center, and then see that that was a blunder instead of a sacrifice (not all people do this, but I say one has to be careful in this).

Anti-chess just forces a forced win if any blunder occurs. Those you played or play anti-chess will surely know this.

I am the worst at Atomic, but this variant is not that hard. You can easily adapt it by practice. This disadvantage of this is blundering a king blast.

Racing Kings is a fun variant, where there is a lot of pins and cut-offs by rooks and queens.

At last, there comes horde. For white, it is good when you just progress by moving your pawns. But it is hard because one has to check that no piece can enter the camp of white. Horde by black is my best variant, I learned a rook-lift pattern where white comes at zugzwang.

These are according to me, you write yours.

@Kumbaya_Haha said in #22:

I just don't like King of The Hill and Racing kings... It’s even worse when you have the black pieces coz in these 2 white has a lot of advantages.
Stockfish does not say so