(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[6.50]
PW[White]PB[Black]C[This is a heavily-AI-aided exploration of some tesuji in Mi Yuting's flying dagger joseki variations.

The lines presented are *far* from exhaustive and there are tons and tons of other variations and possible branch points in this joseki that are not shown, we just focus on a few lines with some interesting tactics.

First branch after move 22]
;B[pd]
;W[qc]
;B[qd]
;W[pc]
;B[nc]
;W[nb]
;B[mb]
;W[oc]
;B[nd]
;W[od]
;B[oe]
;W[pe]
;B[re]
;W[pf]
;B[of]
;W[og]
;B[ng]
;W[qg]
;B[oh]
;W[pg]
;B[rc]
;W[ob]C[First branch: tesujis 1, 2, 3
Second branch: tesujis 4,5]
(;B[lc]C[Go to move 31.]
;W[rb]
;B[sb]
;W[qb]
;B[rg]
;W[rh]
;B[rf]
;W[nh]
;B[ri]C[Tesuji 1: In this line, this clamp is the key move.]
;W[sh]
;B[pa]
;W[nf]
;B[ne]
;W[mg]
(;B[dd]LB[na:A]C[Tesuji 1: Normally, black would need to defend at A, but because of the clamp, it is possible for Black to tenuki here! Although Black following up at A is often still a good idea to reduce how many forcing moves White gets on the outside.

]
(;W[ra]C[Tesuji 1: For example...]
;B[na]
;W[oa]
;B[ma]
;W[rd]
;B[sd]
;W[qe]
;B[rd]
;W[sg]
;B[sc]
;W[sf]
;B[pb]LB[se:B][qf:A][qh:C]TR[ri]C[Tesuji 1:
Because of the clamp stone, white cannot play A or B due to the cut at C.

Black should not play C themselves earlier, to avoid giving white extra thickness, leaving it only until this last moment.])
(;W[ld]C[One of the forcing moves that white gets is this one. This leads to tesuji 2, in one subvariation.]
;B[kd]
;W[me]
(;B[le]
;W[la]C[Tesuji 2: White plays here!

This is white's unique best move and needs to be played at exactly this moment.]
(;B[ma]C[Tesuji 2: If Black cuts, the problem is...]
;W[na]C[Tesuji 2: This becomes sente for White.]
(;B[md]
;W[rd]
;B[sd]
;W[qe]
;B[rd]
;W[ra]TR[sb][rc][pd][qd][rd][sd][re][rf][rg]C[Tesuji 2: With White having a 4-point eye, now Black is all dead.])
(;B[ra]
;W[lb]
;B[mc]
;W[kc]C[Tesuji 2: Snapback.]))
(;B[kb]C[Tesuji 2: Black's correct response is here. ]
;W[ma]
;B[oa]C[Tesuji 2: The situation in the corner is very complex, with ko possibilities, but KataGo believes that this is still close to even by human standards (within a couple of points, depending on the board position, at least for some early openings).]))
(;B[mc]C[Tesuji 2: What if black just connects here and avoids white's M19 tesuji? This is probably usually a mistake and leads to tesuji 3.]
;W[jd]C[Tesuji 3: White plays here! White does not have to do this right away, and there are other options too, but this is an option.]
(;B[kc]
;W[ke]C[White is looking for a result like this, and Black may simply have to accept it, depending on the position.])
(;B[ke]C[Tesuji 3: if Black resists like this...]
;W[kc]
;B[jc]C[Tesuji 3: There are other things Black can try, but this variation illustrates the basic problem Black faces.]
;W[kb]
;B[jb]
;W[la]
;B[lb]
;W[na]C[Tesuji 3: This becomes sente again for white.]
;B[ka]
;W[sc]
;B[sd]
;W[qe]
;B[rd]
;W[ra]TR[sb][rc][pd][qd][rd][sd][re][rf][rg]C[Tesuji 3: Black is all dead now.])
(;B[le]C[Tesuji 3: If Black plays here...]
;W[ke]
;B[md]
;W[lf]
;B[mf]
;W[rd]
;B[sd]
;W[me]C[Possibly black could fight this ko, but it is very heavy for black since the entire quarter of the board is at stake if black loses.]
;B[jc]
;W[ld]
;B[kc]C[Tesuji 3: White's outside thickness is nice, so White is still happy.]))))
(;B[na]C[Tesuji 1: Black often should play here anyways, though, even though tenuki is possible.
]))
(;B[qi]
;W[mc]
;B[nf]C[First branch: tesuji 4
Second branch: tesuji 5]
(;W[nh]C[Go to move 38]
;B[oi]
;W[rf]
;B[qb]
;W[me]
;B[mh]
;W[rb]
;B[sb]
;W[ra]
;B[qa]
;W[qe]
;B[rd]
;W[se]C[First variation: black misses tesuji
Second variation: black plays correctly]
(;B[sf]C[Tesuji 4: This throw-in is the key tesuji that makes this branch playable for black.]
;W[sg]C[First, we can see the followup.]
;B[rh]
;W[sd]
;B[sa]
;W[rb]
;B[ra]
;W[rg]
;B[md]
;W[lc]
;B[ld]
;W[lb]
;B[kd]
(;W[jc]C[Tesuji 4: Possible continuation.


]
;B[ma]LB[la:A][na:C][kc:B]TR[pa][pb]C[Note that black can play here at some point to give white some liberty troubles.
If white blocks A, then black can push at B. If white blocks C, then black gains an approach liberty on the triangled points.

This means that there is a very real possibility for the corner to be a seki, rather than black dying.

This branch is often about even for both sides.])
(;W[sf]LB[ni:A]C[Tesuji 4: White could immediately go for the kill, but it turns out black's thickness and sente is very nice. The value of outside play also depends on whether the ladder escape at A will work later though.]))
(;B[rh]C[Tesuji 4: Why must black throw in? If black plays ordinarily here and misses the tesuji...]
;W[sd]
;B[sa]
;W[rb]
;B[ra]
;W[sf]C[Tesuji 4: White can play like this.]
;B[sc]
;W[rg]TR[sg]C[Tesuji 4: Now we see why black wants white to have a stone at T13 - without it, white has an extra liberty. This is very simllar to the game line, but white's extra liberty means that black will die cleanly in the corner without white having to give up much, unlike the main line.]))
(;W[rh]LB[qe:B][rf:C][pi:A]C[This white move is probably usually not good, but black's refutation is a bit tricky.
White aims at the jump-cut A to escape, and B+C to make very good eyeshape.]
;B[rf]C[Tesuji 5: Black plays the slow-looking but very effective move here, destroying white's shape, and preparing for...]
;W[pi]
;B[qh]LB[rg:B][ph:A]C[Tesuji 5: ... after white tries the jump cut, here! Black threatens both A and B now.]
;W[ph]C[Tesuji 5: Black must be careful about the followup though.]
(;B[rg]C[Tesuji 5: Cutting right away is a mistake.]
;W[md]
;B[qj]
;W[ni]TR[mc][md]SQ[nc][nd][oe][nf][of][ng][oh]C[Black's center becomes extremely heavy, whle white is out.])
(;B[lb]C[Tesuji 5: Black should first exchange here, because white's corner is not alive.]
;W[rb]
;B[sb]
;W[qb]
;B[rg]TR[kc][md]C[Tesuji 5: And only now cut.

Nearby white stones on the top side may change the evaluation of this position though because black is not solid there.]))))
