(;FF[4]
CA[UTF-8]
GM[1]
GN[ Becoming 9 kyu - Lesson 12]
PC[https://online-go.com/review/397979]
PB[Black]
PW[White]
BR[2d]
WR[2d]
OT[Error: time control missing]
RE[?]
SZ[19]
KM[6.5]
RU[Japanese]

(;AB[nc]
;AB[oc]
;AB[od]
;AB[ng]
;AB[og]
;AB[oh]
;AB[nh]
;AB[mk]
;AB[nk]
;AB[nl]
;AB[ml]
;AB[ok]
;AB[mo]
;AB[no]
;AB[np]
;AB[mp]
;AB[op]
;AB[nq]C[Hi! In Lesson #9, we looked at how to make a good shape. In this lesson, we're going to investigate how to destroy your opponent's shape. To do so, you need to learn about bad shapes first. Let's have a look.

Here are four examples. All of them are typical bad shapes. To destroy your opponent's shape, you have to make it look like these shapes. What we usually see is the empty triangle shape at the top. I suppose all of you know that the empty triangle is bad.]
;AW[nd]C[If there's a white stone here, however, it's not an empty triangle. If a white stone is present, the black shape is regarded as a solid position. Let me show you how to deform your opponent's shape.]
)(;B[pd]
;W[dd]
;B[pq]
;W[dp]
;B[qo]
;W[gq]
;B[cf]
;W[ci]
;B[fc]
;W[df]
;B[cc]
;W[ce]
;B[dc]
;W[co]C[This situation comes from a game between two professionals.]
;B[eq]C[Black invaded like this. We often see such a move in handicap games. Even if you're seeing this for the first time, you don't need to worry too much.]
;W[dq]C[To punish Black's invasion, you just have to block here.]
;B[ep]C[In response, Black might push like this.]
;W[eo]C[Then you can strike at the head of the two black stones.]
(;B[fo]TR[fp]C[Because of the cutting point at f4, Black hane won't save the two stones.]
)(;B[gp]C[This attachment doesn't work either.]
;W[fp]C[Black's in trouble.]
)(;B[fp]C[If Black wants to move out, Black has no choice but to make an empty triangle like this. This is exactly the same shape as the one we saw earlier.]
(;W[er]C[Shall we harass Black further? Let's try this hane.]
;B[fr]C[Black has to block.]
;W[dr]C[And then connect here.]
(;B[fq]C[If Black wants to defend the cutting point, Black has to play here. Now look at Black's shape. It's one of the bad shapes I showed you earlier! It's pleasurable to destroy your opponent's position like this.]
)(;B[ip]C[(Black doesn't have to connect now, but it risks losing the f2 stone.)]
))(;W[gn]C[(Knight's move is another way to harass the stones.)]
)))(;B[qd]
;W[dp]
;B[cd]
;W[qp]
;B[op]
;W[oc]
;B[ld]
;W[pe]
;B[pd]
;W[od]
;B[oe]
;W[md]
;B[of]
;W[me]
;B[qg]
;W[lc]
;B[qq]
;W[rq]
;B[pq]
;W[ro]
;B[kq]
;W[ec]
;B[de]
;W[cj]
;B[cn]
;W[fp]
;B[ch]C[This example comes from another professional game. How can White deform Black's shape at c6?]
;W[co]C[Kicking here makes Black heavy. Black has to add a stone to stay alive.]
;B[dn]
;W[fn]C[Now let's say White caps from above.]
;B[fm]C[Attaching is a common escape tactic.]
;W[gm]
;B[fl]C[Then Black stretches. In this case, how can White deform Black's shape?]
(;W[dl]C[If you read Lesson #9 carefully, you'll come up with this answer easily. This placement hits the vital point.]
;AB[dl]C[If Black plays here instead, the group will become safe immediately, as we saw after White e6.]
;AW[dl]C[Therefore, this is the vital point. Now Black's in trouble. First of all, Black needs to connect.]
(;B[em]C[Playing here is the safest way to do so. ]
(;W[gn]TR[fm]C[Then White can connect here, too. Since the black stone is at the marked point, White's shape isn't an empty triangle. But the black group is heavy and will suffer greatly.]
)(;W[ej]C[A move around here would indeed be scary for Black, too. Actually, this move could be better than just connecting, but for the reader who is still coming up to 9 kyu, it's often better to fix obvious weaknesses like g6 first.]
))(;B[en]C[In the actual game, Black didn't want to make a bad shape, so he played here instead. AI says it wasn't a good idea.]
;W[gn]
;B[el]C[Black played here to avoid the empty triangle shape. But he just traded one empty triangle for another.]
;W[ej]TR[dm]C[White played here to move out, leaving e7 as a false eye. White d7 could force Black into making another bad shape. White destroyed Black's shape successfully.]
))(;W[en]TR[em]C[(Below were suggestions by the group.) Stretching here is a good thought, because it might make Black think about making an empty triangle, which is one of the bad shapes I showed earlier.]
;B[dl]C[But in this case, Black would answer here and make a better shape.]
)(;W[em]C[How about this hane?]
;B[en]C[Black can cut and fight. And both players have many weaknesses. But White doesn't need to have weaknesses. White can corrupt Black's shape without leaving bad weaknesses behind.]
)(;W[fj]C[This is a good thought, too, but it's not attacking Black's shape. We were looking for shape deforming moves.]
)))