(;FF[4]GM[1]SZ[13]AP[SGFC:1.13b]

GN[Iain vs. Chris I]
PB[Iain Watson]
BR[NR]
PW[Chris Hayashida]
WR[NR]
KM[0.5]
DT[2001-07-06]
RE[W+57.5]

;B[dd]C[While the 4-4 point is standard on a 19x19 board, it might be an overplay on a 13x13 board. On a 19x19 board, opposing walls on the third and fourth line generate 136 points on the outside to 121 points on the inside. Since it is close to half either on either side,  both sides can either protect the corner or build a wall to influence the center.

On a 13x13 board, however, walls on the third and fourth lines give 88 points to the outside and only 25 points for the inside. On a 13x13 board, an invasion is almost always better than building a wall in the center.]
;W[jj]C[White possibly makes the same mistake. See the previous comment.]
;B[ej]C[The 5-4 point is too high, even in a 19x19 game. This corner is invaded later as a result.]
;W[ic]C[The 5-3 point is probably also too high.];B[id];W[jd]
;B[hc]
(;W[jc]C[Protecting the cut was one option, but white can also answer at J9 or H10.]
;B[gd]C[Good defense for black. Protects against the cut while strengthening the influence at the top of the board.]
;W[gk];B[kj]C[Black starts an invasion of the corner. Usually contact plays to start an invasion are a bad idea, since the invading stone will be short on liberties.]
;W[ki]C[White answers the contact play, and the black stone is already down to two liberties.]
;B[kk];W[jk];B[li];W[lh]C[The double hane is not as dangerous as it looks. This variation on the joseki is discussed on page 150 of Teach Yourself Go, by Charles Matthews. This variation sacrifices a stone to take back the corner. Because of the white group in the upper right, the sacrifice benefits white. Black will have trouble living on the right side. White could have avoided the need to sacrifice if the 4-4 point was not played in the first place.]
;B[kh];W[ji];B[lg];W[lj]
(;B[mi]C[Black extends to escape atari. In the joseki in the book, black plays N6 to take the stone instead.]
;W[lk]C[At this point, the two black stones at L3 and L4 are dead. If black extends, white can chase them down and capture them. If white does not extend, the stone at M4 will be captured by black when black plays at M3.]
;B[fk]C[Black attacks. It is okay to contact because the other black stone at E4 offers support.]
;W[jf]C[White should answer the contact play to keep from falling behind in a capturing race.

The white move extends the group at the top and threatens to cut off the black stones on the right from the rest of the board. If they are cut off, it does not look like there is enough room for the black stones to make two eyes and live.]

(;B[kf]C[Black contacts again. Since black is on the defensive and in need of more eye space, extending to try and make more room (for example, N9) might be better. Black still would have to fight, but might gain more room for two eyes.]
;W[ke]C[This starts to squeeze black. Black has an eye at M6, with a possibility of creating another at L7.]
;B[jg]C[In order to make an eye at L7, black needs both K6 and M8. If black plays one, white can play at the other to make the eye false. However, as the variations show, the eye at L7 may not be important.

Playing black at M9 can also create more eye space.]
(;W[gi]C[White was trying to extend from his wall. Perhaps the 3-3 invasions in the black corners are worth more points. This move does, in a sense, answer the previous contact by supporting the white stone at G3.]
;B[eh]C[Black makes a solid move with a one-point extension, but the corner is still vulnerable to invasion.]
;W[ck]C[White invades at the 3-3 point. If the three black stones in the lower left were much closer to the corner, the invasion would be much harder.]
;B[cj]C[This move protects the lefthand side and helps seal off territory. Protecting in this direction does allow white the possibility of connecting with the group to the right.]

(;W[bk]C[White should hane instead. It would have taken away two points from black's territory.]
;B[bj];W[dk];B[dj];W[ek];B[fj];W[gj]C[This move consolidates white's framework into territory.  The white group in the lower left corner looks like it has enough room to live, so connecting to the group on the right is not important.]
;B[ie];W[je];B[hg]C[This move is big for black. It creates a lot of influence in the center for black, and threatens to connect to the black group on the righthand side. White can still cut off the black group by playing at J7.]
;W[cc]C[White invades the 3-3 point.];B[cd]C[Black probably played this in the right direction. While the invasion is costly, responding in this direction creates a lot of territory in the center.]
;W[dc];B[ec];W[eb]
(;B[fb]C[This is also the double hane joseki played earlier. It may not work, though, because white might be able to connect to the group in the upper right corner. Black at F11 might be safer.]
;W[fc];B[ed];W[gb]
(;B[bc]C[If black were playing the double-hane joseki, the better move would be to play at D12 to take back the corner. This move actually forces white to consolidate his weak groups, without clear benefit.

That being said, it is still a good attack. If white does not respond, black at D12 is double atari.]
;W[db]C[White plays it safe and connects to strengthen his group because there are too many cutting points.]

(;B[gc]C[This move is bad. It forces white to take the at F13 to get out of atari. It also makes an empty triangle. The stone at H11 is already connected to G10 (if white plays at G11, black plays at H10, and vice versa.)]
;W[fa]
(;B[df]C[This move is wasted. Black already owns this territory (or at least has a lot of influence) so there is little gain. B12, G6, or J7 are better moves.]
;W[if]C[White starts to push through.]
(;B[he]C[Blocking at H8 would be better. It might be even better, to connect at J7.]
;W[hf]C[White pushes to cause more problems. Now, even if black connects at J7, the group on the right still might not escape to the center.]
;B[gf];W[ig]C[This cut seals the fate of the group on the right.]

(;B[gh]C[H6 might be a better play. The obvious response makes the move played gote.]
;W[hh];B[gg];W[fi]C[This is not the best move on the board. It does gain two points for white, but black can still block the push to E5 or F6. Protecting weaknesses at B12 or F2 are bigger.]

(;B[fh]C[Black does not need to respond to the pushes. This saves a couple points, but there are bigger plays on the board.]

(;W[bb]C[This move is big. It probably is worth at least 10 points. See the variation if white doesn't play here.]
;B[ac];W[fl]C[This connects the lower left and right corners. The cuts are protected by chase down.]

(;B[ih];W[hi];B[jh];W[lf]C[White plays M8 to make the eye at L7 false.]
;B[kl];W[ll];B[ii];W[ij]C[This move may not be necessary, as the black group on the right is already dead. White plays anyway to be safe, at the cost of one point.]
;B[mh]
(;W[kg]C[This move is a mistake. The stones are already dead, so taking a point in ko only allows black to take for an extra point. White at M9 might be better.]
;B[hb]C[This move is big for black. It is worth at least four points in sente.]
;W[ib];B[ia]C[A three point play for black, but it is gote.]
;W[ja];B[ha]
(;W[fe]C[An overplay for white. This is a one-point net loss. It is even worse that it is gote.]
;B[fd];W[fb]
(;B[ba]C[This move did force the issue, but it appears that black expected a response at B13 instead of A12. Black at A12 would be a better move.]
;W[ab]C[This move both strengthens the lone white stone and forces black to connect at B11 (cutting point on the second line.) Black can get away with making sente plays before connectin, but black needs to connect before playing a gote play.]
;B[ak]C[This is the best move on the board. Black gains another 4 points (taking two from white, instead of black taking two from white.)]
;W[al];B[aj];W[bl]
(;B[ei]C[This move saves one point for black. It is gote, however, so and there is still...]
;W[bd]C[...the cut at B10.]
(;B[be]C[This is the best defense possible. It starts to block off white's advance. The two black stones are already dead.]

(;W[ae]C[White gains an extra two points here.]
(;B[af];W[ad];B[bf]C[This move is necessary to prevent double atari.]
;W[jl]C[White lost a point by playing. Black's three stone chain is just as dead as it was before.]
;B[kf]C[A good move for black. Take the points while you can; the chain is dead anyway. White should have never started the ko.]
;W[le]C[This prevents the cut.];B[mf]C[A good idea for black, but too late. The eye is false.]
;W[me]C[White should have passed here. If black moved again, white could still block. Not playing would also save white another point.]
;B[ge]C[Black does not need to play here. If white plays here, black merely connects at H10.  Black loses a point by playing.]
;W[ga]C[This is the only dame point in the game.];TW[aa][ac]
[am][ba][bc][bm][ca][cb][cl][cm][da][dl][dm][ea][el][em][fm]
[gl][gm][hj][hk][hl][hm][ih][ii][ik][il][im][jb][jg][jh][jm]
[ka][kb][kc][kd][kf][kg][kh][kj][kk][kl][km][la][lb][lc][ld]
[lg][lh][li][lm][ma][mb][mc][md][mf][mg][mh][mi][mj][mk][ml]
[mm]TB[ag][ah][ai][bg][bh][bi][ce][cf][cg][ch][ci][de][dg][dh]
[di][ee][ef][eg][fe][ff][fg][hd]C[End of game

black:
22 spaces of territory
15 black dead stones, 4 black prisoners
3 points

white:
63 spaces of territory (8 upper left, 13 upper right, 42 lower)
1 white dead stone, 2 white prisoners
0.5 komi
60.5 points

If black connected at J11 and saved the group on the right, it would be a net gain of 25 or so ( 11 black dead stones, white loses 14 spaces of territory, possibly black makes some territory.)

If black connected at cutting point at B10, it would be worth 7 points (5 points of territory lost, 2 prisoners.)

Preventing invasion in the upper left, by either playing closer to the corner or playing an additional move to enclose the corner, would be worth a lot of points. It is worth about 24 points (17 points black territory lost, white gains 7 points of territory.)

Similarly, preventing the invasion in the lower left would also be worth a lot. Perhaps it is worth about 16 (6 points white territory, 10 points black territory lost.)]
)
(;C[ If black takes the white stone, it is snapback.];B[ad]
;W[bd];B[af];W[ad];B[bf]))
(;W[ad];B[ae]))
(;C[Black cannot save the two stones.];B[ad];W[ae]))
(;C[If black doesn't move here, it is only a loss of one point.]
;B[bd];W[ei];B[di])
(;B[bd]C[Black should protect the cut first.];W[ei]C[The push only loses one point for black.]
;B[di]))
(;B[ab];W[ba]))
(;W[fd]C[This play would be a one point gain by pushing.];B[fe]
;W[fb]))
(;W[le]C[This is probably a better move.]))
(;B[gl]C[This is an example of one chase down.];W[hl];B[gm]
;W[fm];B[hm];W[im])
(;B[el]C[This is the other.];W[dl];B[em];W[fm];B[dm];W[cm]))
(;C[Assume white moves elsewhere.];B[bb];W[hb]C[White needs to connect, since there is not enough room for the group to live on its own.]
;B[cb];W[ca];B[ba];W[da];B[fd];W[fb]C[Black's cut is defended by chase down.]
;W[bd];B[be];W[ad];B[ae];W[ac];B[ab]))
(;C[Assume black does not respond.];W[fh];B[fg]C[There is only a one point difference.]
;W[ei]
(;B[di]C[This causes a net loss of two points. However, the cut can complicate matters.]
;W[dh]C[White ataris...];B[eg]C[...and black connects. But now the black group in the lower right is vulnerable.]
;W[ch]C[White extends to avoid capture by ladder.];B[el]C[Black must attack the white stones in the corner to survive.]
;W[dl];B[fl];W[aj]C[If white attempts to save them...];B[ai]
;W[ak];B[bi];W[bh]C[White extends his group and takes away one of black's liberties.]
;B[dm]C[Black continues to attack.];W[cm]C[White's shape is dead.]
;B[bl]C[Black plays at the key point and lets white take the stone.]
;W[em];B[fm];W[gl]C[White starts taking away black's liberties.]
;B[al]C[Black must continue to take away white's liberties. White's stones cannot be saved.]
;W[gm];B[cl];W[ah];B[dm]C[It is hard to quantify the net difference in points.]
)
(;B[dh];W[di];B[ci]C[There is a net loss of four points.])))
(;B[hh]C[This looks safe. The result would be about the same, but black might gain 2 points out of it. This move is also sente.]
;W[ih];B[hi];W[hj];B[ii];W[ij];B[gh]C[This probably would be worth about five points.]
))
(;B[hf]C[The groups at J9 and G10 are safe.];W[ig];B[ih];W[jh]
;B[hh];W[hi];B[ii];W[ij];B[gh])
(;B[ig]C[This connection would save the group on the right, in exchange for a few points of territory.]
;W[hf];B[gf];W[he]
(;B[hd]C[Black can try to save the two stones...];W[ge]C[...but then white has a costly invasion.]

(;B[ff]C[If black extends to protect the stone...];W[fe];B[fd]
;W[ee]C[...white advances rather far.];B[ef];W[de];B[ce])
(;B[fe]C[Black can also block...];W[gg]C[...but then the stones on the right are still cut off.]
;B[ff];W[gh]))
(;B[ge]C[It is probably better to sacrifice the two stones and connect with the group on the right.]
;W[hd];B[gh])))
(;B[if]C[This would solve a lot of black's problems, for example.]
))
(;B[hb]C[If Black plays at H12, it but also splits the white groups at the top of the board. White has to worry about making the group on the left live.]

(;W[bb]C[This move is important. It gives white more eye space.]
;B[ab]C[This move attempts to squeeze white.];W[ba]
(;B[bd]C[This move prevents a cut at the second line.];W[ha]
;B[ia];W[ib];B[ga];W[fa];B[ha];W[ja];B[gc];W[fb];B[fd])
(;C[If black doesn't protect...];W[bd]C[White can cut.];B[ac]
;W[ad]C[The three black stones are now dead.]))
(;W[ha]C[White cannot connect to the right.];B[ia];W[ga];B[ib]
)))
(;B[db];W[fa];B[cb]C[Again, at this point the white stones are dead.]

(;W[bc]C[If white attempts to extend...];B[bb]C[...black merely continues to pin them to the edge of the board.]
;W[bd];B[be];W[ad];B[ae])
(;W[hb]C[White is probably better off just giving up on the two stones and connecting.]
;B[bc]C[Black should capture the two stones to keep his two black stones safe.]
)))
(;B[fc];W[fb];B[gb];W[db];B[bc];W[bb];B[bd];W[ab];B[ac];W[ga]
;B[ha];W[fa];B[ib];W[jb];B[ia];W[ja];B[hb]))
(;W[bj]C[The cut is protected by chase down.];B[bk];W[bl];B[ak]
;W[al];B[aj];W[ai]))
(;C[Assume white plays elsewhere.]
(;B[lf]C[If black plays here, he is alive.]
(;W[le]C[If white responds...];B[jh]C[...this makes an eye.]
)
(;W[jh]C[If white attacks, the aji of the stone at M6 to force black to take. If black took the stone earlier, this exchange would be much simpler.]
;B[mh]C[Black has to take...];W[le];B[me]C[...but can still create a second eye.]
;W[md];B[mf];W[ld]C[The eye at L7 is false...];B[ig]C[...but black can escape to the center.]
))
(;B[jh]C[If black plays here...];W[lf]C[...white's attack might create a ko, but the black stones will escape to the center.]
;B[kg];W[le];B[if];W[je];B[ig]))
(;C[Assume white plays elsewhere.];W[lf]))
(;B[le]C[Black can extend to make more eye space and live.]
;W[ld];B[kf]
(;W[ke];B[me];W[jh];B[mh];W[jg];B[kg];W[md])
(;W[me];B[mf];W[md];B[ke];W[jg];B[kg];W[kd])))
(;B[mh]C[Taking the stone still rescues the black stone at M5 from atari. It also still prevents white from playing at N5.]
;W[lk]C[White extends to escape capture.]))
(;W[hd];B[ie];W[hb];B[gc];W[jb];B[he];W[je]C[This variation creates a wall, but now black is strong in the center.]
)
(;W[ie];B[hd];W[ib]C[White has build a wall without substantially strengthening black. The cut at the top is now protected by chase down. This is probably the best variation for white.]
;B[jc];W[kc];B[jb];W[kb];B[ja];W[ia];B[ka];W[la]))
