(;
GM[1]
SZ[19]
AW[dd][jd][nc][dp][qq][qp][po][qm]
AB[pd][pf][pk][pq][np][jp][qr][rr]
LB[qm:5][rr:4][qp:3][qr:2][qq:1]
C[Problem 15. Black to play.  

White has staked out a narrow position with the sequence to White 5, a standard joseki in the Chinese opening. What should Black do next ? ]
(;B[rl]
TE[2]
C[Correct Answer.  

Black should attack the white stones with 1. ]
;W[om]
C[If White jumps to 2, ... ]
;B[nk]
C[... Black keeps up the pressure with 3, attacking White while building influence towards the top. White's stones are still insecure.  <= ]
)
(;B[fq]
C[Failure.  

With respect to the black stones at the bottom, Black 1 is an excellent move, but ... ]
;W[rk]
LB[lq:B][oq:A]
C[... White will slide to 2, intruding into Black's territory on the upper right while securing a base for her stones. Now that her stones are safe, White can aim at Black's territory at the bottom by attaching at A or invading at B.  <= ]
)
(;B[ql]
C[Unsatisfactory.  

The diagonal attachment of Black 1 is inferior to the Correct Answer. ]
;W[pm];B[nk];W[nm]
LB[qj:A]
C[Not only are White's stones secure, but White can also aim at the invasion at A. <= ]
)
)