(;
AB[rb][rc][sc][qb][pc][oc][ob][nb][mb][lb][kb][ja]
AW[hb][jb][kc][jc][lc][mc][nc][od][pd][qd][qc][rd][sd][pa][oa][la][ka]
C[Does White have a ko threat?

Source:
    Test Your Rating (for kyu players)
    Go World #2, Jul-Aug 1977, pp. 35-36]
(;
W[pb];B[ki]
C[Assume that Black ignores White's ko threat.]
(;
W[sb]
C[Correct];
B[sa];W[qa]
C[And Black is short liberties];
B[ma]
C[If Black tries to buy liberties on the left, ...];
W[ka]
C[... White makes the standard throw-in.  Black dies!]
)
    (;
    W[ra]
    C[Slack];
    B[sa]
    C[White has allowed Black to trade the original ko for this new ko.]
    )
)
    (;
    W[na]
    C[Fails];
    B[ki]
    C[Black ignores the ko threat.];
    W[ma]
    C[Connecting out is too slow.];
    B[pb];W[ia];B[qa]
    C[Black lives in the corner.]
    )
)

