What chess opening has the most sideline and variation

My personal thought it was the silican Defense it have so many variations like the Smith mora gambit the bowder attack open close and many more of sideline and variations 

Every opening has a ton of sidelined.

For example:

Wing Gambit

Reti Gambit

King's Indian Attack

Two Knights (Though not very good in this case)

3.Be3 Gambit

3.Bd3

4.c3 Tarrasch (bad for White)

4.Qg4 Winawer

4.a3 Winawer

Winkelmann-Reimer Gambit

4.Bd3 Winawer

4.exd5 Winawer

4.Nge2 Winawer

5.Bd2 Winawer

The Jackal

And there are numerous others that are even rarer.

There are not more sidelines in the Sicilian.  They are simply played more frequently than sidelines of non-Sicilian lines, but other openings have just as many sidelines, as I have demonstrated, or example, in the French.

Also, what does "sideline" mean?  You can wander into any of the ultra-main lines of the Najdorf, Sveshnkov, Dragon, Taimanov, Kan, Rauzer, etc -- and then play a sideline on move 10.

Probably the one with the biggest Grandmaster Repertoire book and/or has the most coverage on a certain opening. But then again, I would focus too much on it. However, there are some stubborn openings that have fewer sidelines like the French as it's not that easy to deviate from the French compared to other openings or if it is an absolutely terrible opening as it would most likely be unexplored and/or losing instantly

Uhm, fewer sidelines?  Did you not read post 3?

ALL of those are sidelines in the French Defense, and that isn't even all of them!

The Sicilian defense for sure. In the ECO codes the Sicilian defense codes go all the way from B20 to B99.

no idea sry

I did but compared to something like 1...e5 or the Sicilian, it will have less sidelines especially within the first few moves. But, out of all the sidelines you mentioned, I've never heard of the Jackal. That one at least has a solid name instead of Winawer Bd3 or something like that

The Jackal is 1.e4 e6 2.d4 d5 3.Nc3 Nf6 4.e5 Nfd7 5.Nf3 c5 6.Bg5 (More common is 6.dxc5)

And that list I gave is not all-inclusive of the French sidelines.  There are others yet.

You could look at which has the most pages in ECO as a first approximation. But .... since most normal openings have far more than I can store in my memory, for practical purposes to me they are all the same.  - Bill

There are many different chess openings that have a lot of sidelines and variations, and it is difficult to say which one has the most. Some popular openings that are known for their many sidelines and variations include the Sicilian Defense, the Ruy Lopez, and the Queen's Gambit.

The Sicilian Defense is a popular opening that is often considered the most complex and theoretically rich opening in chess. It is known for its many different variations, such as the Najdorf, the Dragon, and the Scheveningen, each of which has its own unique strengths and weaknesses.

The Ruy Lopez is another popular opening that has a lot of sidelines and variations. It is named after the Spanish bishop Ruy López de Segura, who wrote one of the first books on chess and popularized this opening in the 16th century. The Ruy Lopez has many different variations, including the Berlin Defense, the Morphy Defense, and the Marshall Attack, each of which offers different challenges and opportunities for both sides.

The Queen's Gambit is a popular opening that is often considered the most solid and positional opening in chess. It is known for its many different variations, such as the Queen's Gambit Accepted, the Queen's Gambit Declined, and the Slav Defense, each of which offers different ways to continue the game.

Overall, there are many different chess openings that have a lot of sidelines and variations, and the best one for you will depend on your individual playing style and preferences.

In my opinion I think that the Ruy Lopez has the most variations. This is because It was created so long ago and has been played so many times. It has a total of 181 variations. My blog has more info - https://www.chess.com/blog/undipin/the-ruy-lopez-opening?ncc=1#first_new_comment

https://www.chess.com/blog/undipin/the-ruy-lopez-opening?ncc=1#first_new_comment this one is linked ;-;

C60 to C99

There are definitely the most in 1... e5, there are many, many, many variations in the:
KGA, KGD, Bishop's Opening, Vienna, Petroff, Ponziani, Four Knights, Scotch, Italian, Ruy Lopez, Giuoco Piano, and there's probably more I'm forgetting about.

It's hard to say as many sidelines may not be named and more sidelines can be discovered. Some openings have a more flexible character though so allow for more possible good moves and deviations.

This also depends on at which point do you define the opening. For example, the Sicilian may not be considered one opening but rather a family of completely different openings the same as e4 e5. Is the Queen's Gambit 1 opening, or a family of openings?

I would say the most flexible and diverse openings are:

• Ruy Lopez
• Sicilian Najdorf
• Nimzo-Indian Defence
• King's Indian Defence
• Queen's Gambit