Nimzo-Indian Saemisch Variation starts after 4.a3

[Allirey]

(https://en.wikibooks.org/wiki/Chess_Opening_Theory/1._d4/1...Nf6/2._c4/2...e6/3._Nc3/3...Bb4/4._a3)

[seccohazy]

I'll just note here, eco codes and opening books (Modern Chess Openings by Nick de Firmian for example) suggest that the Sämisch begins after the continuation 4....Bxc3+ 5. bxc3, which lichess currently designates as "Sämisch Variation, Accelerated". Probably doesn't make sense to have the Sämisch begin before the Accelerated Sämisch.

The opening certainly needs some revision (in addition there's a few other transpositions not accounted for), but I don't have enough clarity to suggest changes yet.

[Allirey]

I'll just note here, eco codes and opening books (Modern Chess Openings by Nick de Firmian for example) suggest that the Sämisch begins after the continuation 4....Bxc3+ 5. bxc3, which lichess currently designates as "Sämisch Variation, Accelerated". Probably doesn't make sense to have the Sämisch begin before the Accelerated Sämisch.

The opening certainly needs some revision (in addition there's a few other transpositions not accounted for), but I don't have enough clarity to suggest changes yet.

I'm honestly not an expert in chess openings naming, just noticed on lichess/analysis that after 4.a3 on the left side where wikibooks' opening info displayed it shows that it's Sämisch Variation and thought it would be nice to have some consistency.

[seccohazy]

I looked into it some more: There's quite a few resources (especially newer opening books) that do call 4. a3 the defining Sämisch move, and for good reason, as there are no sensible alternatives to the 4....Bxc3+ 5. bxc3 continuation anyway.

Now the "Accelerated" added on 5. bxc3 doesn't make any sense to me (and it's the name that sticks if Black responds with the best moves) but that can be addressed in a separate PR.

[niklasf]

Ok, so merging this PR. Thanks both!