But don't worry,

top players also made this mistake.

Let's have look at this game,

Wang Mingwan vs Cho Sonjin.

They are fighting for the Honinbo title.

It's a very important game,

and Wang Mingwan made a mistake

which are usually make by beginners,

didn't see the ladder.

Wang Mingwan is also known as O Meien.

He is a Taiwanese,

so I just use the Chinese name, Wang Mingwan.

OK, let's have a look at this game.

Cho Sonjin took B.

Wang Mingwan took W.

W two-space high kakari.

It's Go Seigen's style.

B keima.

This stone is light.

So W can tenuki.

Locally, if B nobi,

W jumps.

B wedges.

W kakari.

B connects.

W connects.

In the future,

B can keima or extend.

If B nobi here,

W can jump here.

B wedges.

W atari.

B connects.

W connects.

In actual game,

W tenuki and takes this corner.

B shimari.

Then W presses.

B can't retreat.

W will not play like this.

W will attach.

B hane.

W angle wedges.

B kosumi.

W nobi.

B nobi.

W jumps.

B's position is too low.

It's bad for B.

If B nobi,

W bumps.

B blocks.

W hane.

B hane.

It's a large avalanche joseki,

It's playable but not popular now.

In actual game,

B bumps.

W turns.

B descents.

W jumps.

Now B can tenuki.

This point,

and this one,

are miai for B.

In actual game,

B turns to get territory.

This move is very big.

Then W jumps.

The W stone is also very useful.

It's hard to say

this exchange is good or bad.

Now B can't kakari here.

If B kakari here,

W pincers.

With W's influence,

there will be no good for B.

B can kakari here.

If W shimari.

B blocks.

W descents.

Then B jumps.

It's normal.

In actual game,

B kakari here.

It's also Go Seigen's style.

Next

this move

and this move

are miai for B.

If W jumps san-san,

B extends.

W's influence will be useless.

In actual game,

W pincers.

If B jumps,

W jumps.

After this exchange,

B can't extend.

So

B must jump san-san.

W seals B in.

B takes sente to play a splitting move.

Now B has many territory,

and gets the splitting move here.

I think most of players would like to choose B.

W shimari.

If B extends,

W caps.

B jumps.

W peeps.

B connects.

Keima.

B is very heavy.

B can simply jump.

B has already got a lot of territory.

B can give up some territory

just jump to the center.

If W extends,

B caps.

Next B can play here or kakari here.

In actual game,

B keima.

W can extend.

It's too slow.

B jumps.

B's shape is good and B's speed is fast.

So W caps.

It's the vital point.

B keima to get out.

W jumps.

B peeps.

W connects.

In actual game,

B keima.

It's too greedy.

The corner is already a living group,

the keima is just for territory,

not for life.

B should attach directly.

W can't hane here.

B nobi.

W bumps.

B nobi.

Now you see,

This stone is just at a very good position.

If W connects,

B turns.

B is comfortable,

and W has a cutting point here.

If W presses,

B nobi.

W is hard to reinforce.

If W connects,

B turns.

W's shape is bad.

In actual game,

when B attaches,

if W hane here,

B cuts.

W atari.

B nobi.

W nobi.

B turns.

W connects.

Compare to the actual game,

W doesn't have a stone here.

So B is much easier to fight.

B can simply nobi.

W connects.

B kosumi.

W jumps.

It's a fight and B will not be afraid.

W still has a weakness here.

All B can just double atari.

W nobi.

B captures.

W kosumi.

B is also not bad.

In actual game,

B keima.

This move is very big,

but not urgent.

B is too greedy.

W will not respond,

and W also doesn't have a proper move to respond.

If W attaches,

B bumps.

W has too many cutting points.

So W certainly tenuki.

W caps again.

B contacts. It's a probe.

If W kosumi to protect the corner,

B descents.

W hane.

B turns.

Now B is a living group.

W's center is too thin,

if B is a living group.

In actual game,

W nobi.

In the future,

if W reinforces here,

the exchange would be very bad for B.

But if B plays in the future,

B hane.

W hane.

B kosumi.

W atari.

B connects.

W connects.

B can get the corner.

B can also consider to attach.

W hane.

B budges.

If W atari,

B just makes the ko.

The ko is very, very heavy to W.

So B played a probe here,

and B got some aji.

Then B attaches.

You see now W has a stone here.

If B attached directly before the keima,

B would be much better.

W hane.

B cuts.

Now W can't nobi.

If W nobi.

B nobi.

W nobi.

B kosumi.

W reinforces.

B presses.

W turns.

B keima.

B can push here,

and the kosumi is also B's sente.

So B is a living group.

W is a floating group and very heavy.

This diagram is bad for W.

In actual game, W atari.

B nobi.

The sequence is very good.

B can't push.

W atari.

And atari here.

B will be killed.

In actual game,

B turns.

Then W connects.

This exchange is bad for B.

It's B's absolute sente.

B should reserve.

If B didn't make this exchange,

just played like the actual game,

B atari here.

W connects.

Then B pushes.

W still can't hane.

Because,

this is B's absolute sente.

W still has to jump.

Then B attaches.

W hane.

B connects.

W still has to reinforce here.

Because this B's sente.

So if W still has to play in this way,

why made this exchange?

If B didn't make this exchange,

this move will be B's sente.

B will be easy to make a life.

And B also has this technique.

B can attach.

If W atari,

W nobi.

W connects.

This result is good for B.

W's moyo is gone.

In actual game,

this exchange has been made,

so the kosumi is not B's sente.

Of course, B also doesn't have this technique.

In actual game,

B just hane.

B plays like this,

because B wants to make use of this stone

and play this technique.

If W nobi,

B will use this technique.

So W double hane,

and tries to get a sente.

B atari.

W connects.

B nobi.

Now it's honte for W to nobi.

Wang Mingwan didn't notice the ladder.

So W presses.

W may think, B would hane.

If B hane,

W atari.

B connects.

Then W turns.

B made a very bad exchange here,

then W still gets the corner.

This diagram is very good for W.

In actual game,

B nobi.

Now W should have realized the ladder.

It's honte for W to hane.

B hane.

W nobi.

B jumps.

Though this move becomes a bad move,

W has to play in this way.

In actual game,

W didn't even think of the ladder.

W still nobi.

B atari.

W atari.

B counter atari.

Now the ladder appears on the board,

W still responds.

That's very funny.