(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Chinese]SZ[19]KM[0.00]
C[常形讲座 01 星大飞尖
吴新宇 六段
天元围棋

Common Shapes Lectures 1 Star point large knight's corner enclosure
Wu Xinyu 6p
tianyuanweiqi

https://www.youtube.com/watch?v=MR_DukGjK3k&list=PL9mIJo0rMVCNM5iMjWB_eu0KKExj-ZKcV

Translated by Daniel Hu 6d
20220920

29:46

Wu Xinyu 6p
1986 Turned pro
2000 6p
1987 National Youth Champion
1993 Young Stars cup 3rd
2001, 2002 CCTV cup last 8
many times National Team championships, Chinese League A top 3
Go teaching work 12 years
Brought up 20+ professional players

Hello to viewers. Welcome to Tianyuanweiqi channel. I am Wu Xinyu, bringing to you Common Shapes Lectures.

The topic of Common Shapes is about the shapes Weiqi fans often meet in games. We will analyse the correct counters for both sides, preparing everyone to use it in their games.

Let's look at the Go board.]
;B[pd]
;AW[jc][mc][qi]AB[oc][qg]C[This is a star point, large knight's enclosure, defence shape. We won't say much about how this appeared, just first Q16, then R13, then P17 in response to N17.

Then what techniques does W have in the corner? This is the topic of our programme.

...

In conclusion, I feel that when W isn't very thick around, the 3-3 point is wise. It isn't easy for B to fight back. W will get some territory in sente.

But when W is thicker than B on the outside, W should choose the 2nd line point, or even the 3rd line point, which are better than the 3-3 point.

We hope viewers will memorise some of these simple variations.

Thank you for watching, see you next time.]
(;W[qc]C[The first type is pointing at 3-3. This is the most easy to think of and most common.

...

Let's make a simple conclusion. Upon pointing the corner, W should give way in the corner and accept P18. That is both player's correct sequence.

B accepts it relatively easier, but W also gets some territory in sente.

B doesn't fear W directly living with diagonal.

Overall, W is slightly unsatisfied.]
(;B[qd]C[The most correct method is to block.

W has two ways.]
(;W[ob]C[The first type is attach underneath. This is gives an opportunity for B to make a choice.]
(;B[pb]C[The correct choice is hane inside. When W has support around, B can only retreat slightly.]
;W[nb]
;B[qb]C[W pulls back, B clamps.

Both sides peaceful solve the problem of the corner. W gets attach under and pull back in sente. But B also stabilises the corner territory with no worries. Both sides have profit.

If you must say which side has profited, with the advantage, the feeling is that B is slightly more satisfied.

That is, B's corner originally wasn't very thick. When the large knight's move played further than the small knight's move, B has extended one more move, so if B can still defend the corner, B is relatively satisfied.

If W is perhaps unsatisfied, W has another method.

...

This is both player's correct sequence after the 3-3 point.
])
(;B[nb]C[B hane outside isn't great.]
;W[pb]
;B[nc]C[W pulls back, B connects.]
;W[mb]C[W can naturally clamp down.]
;B[na]
;W[rd]
;B[re]
;W[rb]
;B[sd]
;W[rc]C[It can be said that W's lives very big in the corner.

Whereas B's outside isn't very thick. This loses relatively much territory.]))
(;W[pb]C[The intention of diagonal directly is to directly steal the corner.]
(;B[ob]C[B must block.

compared to being able to attach under and pull back, W has lost space for living.

...

The simple conclusion is that B doesn't fear this.]
;W[rd]C[Hane is to increase eyespace to live.]
(;B[rb]C[B's correct move is to point.]
;W[rc]C[W must connect]
;B[re]C[Then B blocks, this is the correct sequence.

Next for W to live, W must play a rather crude sequence.]
;W[sb]
;B[ra]C[Now B has both Q19 and T16 hane.]
;W[oa]C[W must use a very crude move to first prevent this hane.

This is a very costly technique.]
;B[na]
;W[pa]
;B[mb]
;W[sd]C[This can be called a stubborn life. Although it can just barely life, the technique is really not profitable. Because the outside N17 has been overly harmed.]
;B[lc]C[Upon the hane up, B has become very thick towards the outside. And there are even many points locally. And K17 will be very affected too.

And locally, W's corner territory is very small.]
(;W[]
;B[se]C[later the block has sente aji.]
;W[]
;B[sa]C[If you don't play, they can directly atari from inside]
;W[pc]C[It turns into a thousand year ko.])
(;W[qb]C[Later if W kills B, they can only play like this]
;B[se]
;W[qa]C[There are actually only 5 points inside.]
;B[pc]
;W[sa]C[This result is unacceptable for W. Only if B's outside has almost no use whatsoever, can W choose this variation.]))
(;B[re]C[If you casually hane, this is a crude move.]
;W[rb]C[W can block with tiger. This is ko for life.]
;B[sd]C[Some players think that if the opponent sets up a ko, then I should start the ko. But everyone should watch out. This ko is, although it looks like W that is ko for life. In actual fact it is B that is heavier.

...


So this ko is relatively heavy for B, lighter for W. B can't start the ko without much consideration.]
;W[sc]C[Because after W starts the ko.]
(;B[rc]
;W[]
;B[sb]C[If B wins the ko, it is this sort of result. B recaptures their own corner.])
(;B[]
;W[se]C[However, if the ko is won by W, then the whole B's outside group turns into an isolated group.]
;B[]
;W[rf]C[After W ataris, the whole outside is isolated.
])))
(;B[rc]C[B cannot simply retreat.]
;W[rb]
;B[rd]
;W[ob]C[W connecting across lives much too comfortably.])))
(;B[pb]C[Weiqi fans who like to kill might ask if diagonal works. But this is an overplay.]
;W[re]C[Because even if W plays the most simple knight's move, B has no way to kill W.]
;B[qe]
;W[rf]
;B[rg]
;W[qf]
;B[pf]
;W[qd]
;B[pe]
;W[qb]C[Even W playing the most simple way, not cutting Q13, B has no way to kill W. ]
;B[sf]
;W[rd]C[Even if you hane, W can just connect. Due to many cutting points, B can't continue.

Then as soon as W lives, B's outside will have a life and death problem.]))
(;W[re]C[The second way of playing is to steal B's area from here.

Making theory from feeling, I think that this move seems stronger than pointing 3-3.

If this is stronger, then we should investigate it more thoroughly.

...

That is to say that W's 2nd line point is a very good technique. Here I feel that it can be recommended to everyone. If W doesn't have many problems on the outside, is slightly thicker, then my feeling is the 2nd line point is better than the 3-3 point.]
(;B[qe]C[Diagonal seems to be the vital point of defence.

...

B can only diagonal, this is the best defence.]
(;W[rf]C[B doesn't fear W retreating here.]
;B[rd]C[The difference with not have gotten R15 in sente is very big.]
;W[qf]
;B[pf]
;W[rg]C[Crawling back]
;B[pg]C[Even if B just connects, then B's corner is relatively satisfactory, and the shape also. But although W broke some of B's points, because W still has some weaknesses, so W's gain is quite small.]
;W[]
;B[qj]C[B still has this sort of severe attachment.])
(;W[rd]C[If you have pointed, then you must extend inside. This is the most relentless move.

...

If R17 diagonal is also not good, then W's this move can be said to work.]
(;B[rf]C[If B tigers trying to kill W unconditionally.

...

So B's tiger has some problem.]
;W[qc]C[W just diagonals]
;B[pb]
;W[qb]C[Although W hasn't lived inside, but B also has no way to kill.]
(;B[se]
;W[pc]C[B's outside has problems]
;B[ob]
;W[od]C[B's own shape has too many weakness to kill W.])
(;B[md]C[Another even alternative is to strengthen the outside to prevent Q17.]
;W[lc]
;B[nd]C[Whether pulling back or otherwise some other techniques to force W to add a move to live inside. Depending on the surroundings, this may also be acceptable for B.]))
(;B[qc]C[If B just diagonals here, W also doesn't need to fear.]
;W[rc]C[W can first crawl in and it is already uncomfortable for B.]
(;B[rf]C[If B still returns to tiger,]
;W[qb]
;B[pb]
;W[qd]C[B's outside isn't thick enough outside, so it isn't easy to continue.

If it comes to a ko fight it is clearly heavy for B and light for W.]
;B[pc]C[If connect without ko]
;W[qa]C[W descends, a good move, and there is even less way of continue.]
;B[sb]C[B can only point to kill, making a bent four in the corner, there is even less way of killing W.]
;W[rb]
;B[sa]
;W[se]
;B[sc]
;W[pe]
;B[qf]
;W[oe])
(;B[rb]C[If B hane blocks]
;W[qd]C[As pinching is sente, W simply ataris out.])
(;B[qb]C[So B can only descend.

]
;W[rf]C[Then W extends. If B still continues trying to kill in this shape, it is too tiresome.]
;B[rg]
;W[qf]
;B[pf]
;W[pg]
;B[ph]
;W[og]
;B[qh]
;W[rb]C[W has too many liberties in the corner, so it is very difficult for B to continue. W has many techniques.

Even if B is able to just capture W, then W can short liberties around O15 or P11 etc. Even if B manages to win a capture race with all W's stones, this is a loss for B. Because B originally had a stake in the corner.]))))
(;B[rd]C[If B chooses the standard attachment, this appears too soft.

...

Then although we said this feels like B was wronged, if W is relatively strong around, then this is also a wise man looking after his own hide (mingzhebaoshen) sort of technique.]
;W[qe]
;B[qd]
(;W[rg]C[W can simply attach across and B's corner has become very small.])
(;W[pf]C[Of course, W can more actively diagonal out, putting B's one R13 stone in great danger.

This can be considered.])))
(;W[qe]C[There is also another even more severe move. This is also difficult for B to deal with.

But this does come with a prerequisite that W must be relatively thick on the outside.

After the invasion, B has only 2 moves.

...

Everyone should watch out that this point is relatively strong move.

I feel the correct move should be to cover with Q15, and let W connect underneath.]
(;B[pe]C[pressing on top

...

A relatively simple variation. It should be memorised by everyone.]
(;W[qf]C[W bumps]
(;B[pf]
;W[rg]
(;B[pg]
(;W[rh]
;B[qd]C[B defends. This can be said to be W taking the corner in sente.

For B, sometimes when W is relatively thick on the outside, then B can only retreat a little to let W get some profit.])
(;W[qd]C[Of course, more aggressive can be to push inwards.]))
(;B[qd]C[B can also directly turn with the S14 follow up.

This is to take sente.]
;W[pg]C[but even if W responds, this atari is also worth a move, also very big. It isn't necessary profitable for B.]))
(;B[pg]C[Extending upwards is very overplay. A problem already appears.]
;W[pf]
;B[of]
;W[rg]
;B[rh]
;W[rf]
;B[qh]
;W[qc]C[W can jump to live and there is also a cutting point on the outside. This is difficult for B.]))
(;W[qd]C[W also has another move to push inwards.

...

Hence B doesn't need to fear pushing first much.

]
(;B[qf]C[B can't play on the outside.]
;W[qc]C[This isn't great for B.])
(;B[qc]C[A more stable more is to tiger block.]
;W[rc]
;B[qb]C[Simply extend.]
;W[qf]C[After crawling, when W bumps, ]
;B[pg]C[B can pull back. It wasn't good for B before, but is now.]
;W[rg]
;B[rh]
;W[rf]
;B[qh]
;W[pf]
;B[of]
(;AE[qb][qc][rc][qd]C[Comparing to this shape, W's pushes have become very bad exchanges.]
(;W[qc]C[Here, you can just jump in])
(;W[qd]
;B[qc]
;W[rc]
;B[qb]))
(;W[ri]C[Even if you get to clamp once]
;B[sh]
;W[rb]C[Now W must still continue living inside.]
;B[ra]
;W[sd]
;B[og]C[B connects properly on the outside. W's profit is very much limited.]))))
(;B[qd]
(;W[qf]C[The strong follow up here is to bump. This is very dangerous for B.

...

That is, after R16 block, B already finds it hard to deal with this shape after W bumps.

Whether R16 is good or bad requires more research.

Overall I feel Q15 pressing from above is the more stable and reasonable move.

...

I feel that it is difficult for B to deal with here so I think R16 isn't as good as Q15.]
(;B[pg]C[extending is the easiest for everyone to think of, but it isn't necessarily good]
;W[rg]C[W can hane first.]
;B[rh]C[hane block seems the only move]
;W[oe]C[All of a sudden, B's 3 stones are disconnected from the corner. B will find it very difficult to fight after this.]
(;B[pe]C[Watch out that you can't push and cut.]
;W[pf]
;B[of]
;W[og]
;B[nf]
;W[ph])
(;B[qh]
;W[of]C[Whatever B plays, W connects, afterwards]
;B[]
;W[re]C[This sort of bend and so on are all sente against the corner, which has very little territory. The outside stones will also suffer an attack. This diagram is completely unacceptable.]))
(;B[qh]C[If B can't extend, it is already difficult for B. The strongest move left is only bumping.]
;W[of]
;B[pi]
;W[qj]C[Both sides turn into a fighting attitude. But overall, W invading B's empty area and cutting B into a isolated group and there are many sente moves against the corner (S16, S15, O18). This is quite a loss for B.]))
(;W[pe]C[pushing up is a crude move, everyone must watch out.

...

It is an easy mistake for everyone to make.]
;B[oe]
;W[pf]C[Some players might think that this turn perfectly just escapes.

But this shape is really just too bad.

...

Normally this is not very good for W.

...

Don't play this sort of shape without much consideration.]
;B[re]
;W[rf]
;B[rd]C[meeting this hane connect, W suddenly becomes a dumb shape]
;W[qf]
;B[of]
;W[pg]C[To spend so many moves to only capture one stone, the profit is very much limited.

From the shape, we see two bulky fives. This can't be called good for W.])
(;AE[qi]AW[qj]C[An extra point to note is that sometimes W's stone is further on the right. Then upon R15, B can block R16.

So that if the stone is further, R15 isn't as severe.]
;W[qf]C[Because this doesn't really work any more.]
;B[pg]
;W[rg]
;B[rh]
;W[oe]
;B[pe]
;W[pf]
;B[of]C[One line difference.]))))