Figure 2 Move 51 to 100

a18=62 b2=82 b3=81 b4=77 b11=78 b13=79 b17=61 b18=60 c3=80 c6=73 c7=C c8=74 c17=57 c18=56 d4=. d11=71 d16=. d17=59 d18=53 d14=A d19=58 e2=88 e6=75 e8=76 e13=69 e14=65 e15=63 e17=B e18=54 f2=84 f3=87 f4=83 f12=70 f13=68 f14=64 f15=52 f17=. g2=85 g3=86 g4=90 g5=91 g6=100 g17=66 h2=89 h3=93 h4=94 h5=96 h14=72 h15=55 h17=51 h18=67 i3=92 i4=95 i5=98 k3=97 k4=99 k12=. l9=. l10=. l11=. l12=. m9=. m10=. m11=. m12=. m13=. n12=. n13=. n14=. n15=. n16=. n17=. n18=. o12=. o13=. o14=. o15=. o16=. o17=. o18=. p11=. p12=. p13=. p14=. p15=. p16=. p17=. p18=. q4=. q12=. q13=. q14=. q15=. q16=. q18=. r8=. r11=. r12=. r13=. r14=. r15=. r16=. s13=. s14=. s15=. s16=.

\begin{figure}\gofontsize{15}
\begin{displaymath}
\showfulldiagram
\end{displaymath}\begin{center}Fig.~2 Move 51 to 100\end{center}\end{figure}

White 53 is too aggressive. This belongs to the old way of playing go which stresses giving no place for the opponent to settle down. But at this time, since black is unable to get settled down immediately at the right edge, it's not necessary for white to press so hard on black. White 53 should be played at A. Even if white wants to press hard on black to avoid black to ignore him, white should play at B.

But black 54 is unreasonable. At this time, black itself is very weak here, there is no time for black trying to disconnect the white groups. Black 54 should be played at 1 as shown in Dia. 6, if white plays 2, black can play 3 to get a good shape and reduce some white's future territory while white has to worry about black's escaping from A. So when black plays 3, white has no effective measures to attack black here.

d4=. d14=2 d16=. d18=. f15=. f17=. h15=1 h17=. i17=3 k12=. l9=. l10=. l11=. l12=. l13=A m9=. m10=. m11=. m12=. m13=. n12=. n13=. n14=. n15=. n16=. n17=. n18=. o12=. o13=. o14=. o15=. o16=. o17=. o18=. p11=. p12=. p13=. p14=. p15=. p16=. p17=. p18=. q4=. q12=. q13=. q14=. q15=. q16=. q18=. r8=. r11=. r12=. r13=. r14=. r15=. r16=. s13=. s14=. s15=. s16=.

\begin{figure}\gofontsize{10}
\begin{displaymath}
\showdiagram a-t:8-19
\end{displaymath}\begin{center}Dia.~6 \end{center}\end{figure}

After white makes a jump (55), black 56 is too early to invade the corner, especially black's 62 is not urgent. As in Dia. 7, black should play 1 first to get out, when white plays 2, then black comes back to invade the corner. If the game is proceeding this way, black's situation is much better than in Figure 2.

b18=11 c14=2 c17=4 c18=3 d16=. d17=6 d18=. d19=5 e14=1 e18=. f15=. f17=. h17=. h15=. h16=10 h18=7 g17=9 i18=8 k12=. l9=. l10=. l11=. l12=. m9=. m10=. m11=. m12=. m13=. n12=. n13=. n14=. n15=. n16=. n17=. n18=. o12=. o13=. o14=. o15=. o16=. o17=. o18=. p11=. p12=. p13=. p14=. p15=. p16=. p17=. p18=. q4=. q12=. q13=. q14=. q15=. q16=. q18=. r8=. r11=. r12=. r13=. r14=. r15=. r16=. s14=. s15=. s16=.

\begin{figure}\gofontsize{10}
\begin{displaymath}
\showdiagram a-n:8-19
\end{displaymath}\begin{center}Dia.~7 \end{center}\end{figure}

White 63 is the crucial point for attacking. Black has to play 66 (point-losing move) in order to avoid being cut. After 71, black's situation is more unfavorable. Black 72 is not urgent, this move should have been played at C in order to keep the balance of the whole board's territory regardless what happened! When white plays 73, black looks like he is going to lose.

In the first half game, Zhou made use of several questionable moves by Guo and took advantage by actively attacking black. This shows his good whole-board balance sense and flexible playing style.

Black 74's invasion is tenacious. If black couldn't mess up the situation here, black might have no chance to compete with white. White 77 starts a wrong sequence, this move should have been played as 1 in Dia. 8. After black's connection, white can get out by 3 and 5. As several black groups are not safe all together, black will have a difficult struggle. In Dia. 8, it is not good for black to play A any more, because white can play B, black C, white D, black E, white F.

a18=. b4=6 b5=7 b9=B b10=D b11=A b17=. b18=. c6=. c9=C c10=E c11=F c8=. c17=. c18=. d4=. d11=. d8=2 d9=1 d16=. d17=. d18=. d19=.

e6=. e8=. e13=. e14=. e15=. e18=. f3=4 f5=3 f10=5 f12=. f13=. f14=. f15=. f17=. g17=. h14=. h15=. h17=. h18=. k12=. l9=. l10=. l11=. l12=. m9=. m10=. m11=. m12=. m13=. n12=. n13=. n14=. n15=. n16=. n17=. n18=. o12=. o13=. o14=. o15=. o16=. o17=. o18=. p11=. p12=. p13=. p14=. p15=. p16=. p17=. p18=. q4=. q12=. q13=. q14=. q15=. q16=. q18=. r8=. r11=. r12=. r13=. r14=. r15=. r16=. s13=. s14=. s15=. s16=.

\begin{figure}\gofontsize{10}
\begin{displaymath}
\showdiagram a-n:1-19
\end{displaymath}\begin{center}Dia.~8 \end{center}\end{figure}

When white plays 81, black 82 is unreasonable and makes very few points. Black 82 should be played at 86 to free itself from the predicament. White 83 and 85 are severe, although black 88 is very inconvenient, it is a must for black. Otherwise, black doesn't have enough territory to compete if black gives up this corner.

White 93 and 95 makes a strategic mistake to get one black stone. As in Dia. 9, white 1 and 3 is a beautiful sacrifice technique, after white 7, white takes overall advantage, because the central black group is very weak. When black plays 8 to strengthen the center, white 9 and 11 are sente moves. If the game proceeds this way, black has no target to attack and has no hope for the game.

a18=. b2=. b3=. b4=. b9=11 b11=. b13=. b17=. b18=. c3=. c6=. c8=. c17=. c18=. d4=. d8=10 d9=9 d11=. d16=. d17=. d18=. d19=. e2=. e6=. e8=. e13=. e14=. e15=. e18=. f2=. f3=. f4=. f12=. f13=. f14=. f15=. f17=. g1=6 g2=. g3=. g4=. g5=. g17=. h2=. h3=2 h14=. h15=. h17=. h18=. i2=4 i3=. i4=1 k2=5 k3=3 k4=7 k12=. l9=. l10=. l11=. l12=. m9=. m10=. m11=. m12=. m13=. n12=. n13=. n14=. n15=. n16=. n17=. n18=. o12=. o13=. o14=. o15=. o16=. o17=. o18=. p8=8 p11=. p12=. p13=. p14=. p15=. p16=. p17=. p18=. q4=. q12=. q13=. q14=. q15=. q16=. q18=. r8=. r11=. r12=. r13=. r14=. r15=. r16=. s13=. s14=. s15=. s16=.

\begin{figure}\gofontsize{10}
\begin{displaymath}
\showfulldiagram
\end{displaymath}\begin{center}Dia.~9 \end{center}\end{figure}

After black 100's atari, the upper-left corner white group stones are already hurt, and black's central group is greatly strengthened.