(;
AB[ec][bd][cd]
AW[be][ce][de]
PL[W]
C[White plays.

Source:
Go World #23, p. 44
Basic Fighting Techniques
Miyazawa Goro 6P]
(;
W[ci]
C[Of course, White can make an extension here, but ...];
B[fd]
C[... Black can reinforce the corner.  This exchange favors Black, because White no longer has the sequences in the variation.]
)
    (;
    W[dc]
    C[White takes advantage of Black's weakness with this must-know tesuji.]
    (;
    B[dd];W[ed]
    (;
    B[db]
    C[If Black saves the corner stones this way, ...];
    W[fc];B[eb];W[fb]
    C[... White has these 2 outside forcing moves.  White seals in the corner group.  Moreover, ...]
    PL[W];
    B[bb]
    C[... Black has to defend the corner to prevent White from making a placement here.

The reader can work out what happens if Black omits this play, and then White plays on this 2-2 point.]
    )
        (;
        B[fd]
        C[If Black counters here instead, ...];
        W[ee];B[eb];W[cb]
        C[... White can gouge out the corner.];
        B[cc];W[ad];B[db];W[bc];B[dc];W[bb]
        C[Now Black has to seek life on the top, but would not be able to make a strong shape.]
        )
    )
        (;
        B[db]
        C[Black can hane here, but ...];
        W[dd];B[cb];W[cc]
        C[... White is happy to push through.]
        (;
        B[bb];W[bc]
        C[White picks up 2 stones.]
        )
            (;
            B[bc]
            C[Black can block to save the 2 stones, but ...];
            W[bb];B[ab]
            (;
            W[ba];B[ca];W[eb];B[aa];W[fc]
            C[... White can capture a stone with a ladder for outside thickness.];
            B[ad]
            C[And Black still has to descend here for the 2nd eye.]
            )
                (;
                W[eb]
                C[Note that White can also cut here.];
                B[fb]
                C[If Black captures the cutting stone, ...];
                W[ba]
                C[... White uses yet another must-know tesuji to capture 4 stones.]
                )
            )
        )
    )
)

