BQM 213 / Summary

Black to play  

The initial question was if Black should reduce with a or invade with b. Later, though, the debate expanded to the question whether the big point c has priority over the lower side. The temperature of the lower side is affected by the possibility of a corner invasion at d and the protection of it at e.

The invasion  

The invasion of was commonly judged abusive or at least counter-intuitive and unnecessarily complicating things. Conventional wisdom urges to drive the black stone towards White's thickness at the left. A more prudent approach at b was also suggested.

Some voices went against conventional wisdom and advocated the expansion of White's framework, sacrificing the White stone at the highest possible profit, playing d or e.

Another possible answer, the corner invasion at c was also suggested and thoroughly analyzed.

Extension cum attack  

With a possible continuation like this. takes the big point while attacking Black's center group.

Who attacks whom? The roles are changed.  

tderz: After , White (or a for also clearly demonstrating the bad white shape) to defend against the black cut b,
Black attacks gladly with .
Being behind in the running fight does not allow white to play .
(Even if there were great shinogi experts at play, would they then first let neutralize their possible use of their own white wall?)

Black continuation  

If White jumps, Black can attach at a. The continuation is yet to be discussed.

Take the corner 1  

The corner invasion is not such a good reply, because Black forces White to a low position and puts his invading stone to good use.

Take the corner 2  

This way Black goes too easy on White. White's cut off stone still has potential.

Turn the tables  

Sacrificing and expanding the framework seems to give Black easy territory but the expansion is an original approach.

Black reduction - expansion  

If Black reduces the White framework while expanding his own, White can do likewise at the other side at a, or reply to with b or c.

Too easy  

probably is too mild, leaving the other expansion to Black as well.

Black reduction - expansion  

If enters the corner, Black takes the initiative to play again.

Fighting  

If takes the other expansion point, Black can attack at . makes points while continuing the attack. A difficult local position follows.

Top first  

is big, but is probably bigger.