(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[AGA]SZ[19]KM[7.50]
PW[gaseimasha]PB[gaseimasha]
;B[qd]
;W[dc]LB[de:B][pp:C][qp:A]C[A move at "a" essentially aims at a territorial style. It waits for white to approach from the left, after which black will probably try to settle his shape in sente and then play elsewhere, either to reduce white's probable thickness, or white's probable moyo.

A move a C is a little more active. It aims at the shimari next at P17, after which, black has a good framework in the side from which to expand operations. Black will then expect white to, at some point, invade. At which point, black can try and make profit by attacking.

A move at B is very active, and aims at building influence early. That influence, hopefully, will lead to some future profit later in the game, the tradeoff is that black will probably exchange thickness for white gaining territory in the corner.]
;B[de]LB[cg:A][dp:C][pp:B]C[The pincer at "a" is a fighting move, with the possibility of connecting at C15, which black has to deal with. The main usefulness of a move like "a" is that it resist's simly giving black thickness. Whereas a joseki like C15 would be simply yielding black center thickness while sealing white in. A fight ensures that black has to run, especially since a shimari at P17 would be awkwardly placed.

Alternatively, white can allow black to have influence and simply play a move like "b", which takes another empty corner. This is feasible because black can not kill the D17 stone with one more move, so after a sequence like Q4, C16, White can play a move like E16, Black E15, White H17, and white has a living shape.

But why Q4 instead of D4?

The reason is because of R16. A shimari at P17 would have influence down the bottom side, and a white stone on the bottom right star point would do well to limit black development along the side and make the shimari awkwardly placed. Since black is committed to developing thickness with the D15 stone, a joseki in the upper left corner is likely to happen. If white manages to get sente, then a move at "be" would be valuable in the fighting that would ensue. Or, if black get's sente and plays at "c" then white would need to be aggressive.]
;W[pp]C[(See variations)]
(;B[ec]
;W[ce]
;B[cf]
;W[df]
;B[cd]
;W[dd]
;B[be]
;W[ee]
;B[ce]
;W[fc]
;B[db]
;W[eb]
;B[cc]
;W[ed]
;B[cb]
;W[dg]C[White is better.])
(;B[cd]
;W[ee]
;B[cc]
;W[ed]
;B[ef]
;W[ce]
;B[dd]
;W[df]
;B[cf]
;W[dg]
;B[db]
;W[ec]
;B[eb]
;W[fb]
;B[ff]
;W[gf]C[Messy.])
(;B[cc]
;W[ee]
;B[cd]
;W[dd]
;B[df]
;W[fc]C[DDK.])
(;B[fd]
;W[ce]
;B[cf]
;W[df]
;B[dd]
;W[cd]
(;B[cg])
(;B[cc]
;W[bc]
;B[cb]
(;W[cg]
(;B[ec]
;W[bf])
(;B[ef]
;W[bf]))
(;W[ef]
;B[ec]
;W[cg]
;B[bb]
;W[bd]LB[dp:A]C[Joseki.

However, my initial estimate was off, as now black has sente, and will play in the last available corner. Because of the surrounding position, black is slightly better off, so White Q4, would have been better played at D4.

]
;B[dp]LB[nc:C][cn:A][fq:B]C[A move at "a" uses the thickness gained in the previous joseki to set up a framework along the side. Black must be careful if he pincer's, because white can easily double pincer thanks to the support stone at Q4 and turn the situation into a running battle between two weak groups. Unfortunately, with the white support, black would get the worst of it.

Nor does black have a good move to settle group fast that covers ground quickly in that corner, either, so white can expect black to make an approach move of his own in the bottom right to complicate things at O3, or, if black wants to play solidly,he can make an approach move at R6. This, however, severely limit's the chances of D4, so black should not blithely play like this.

An approach move at "b" has the same idea, but this makes poor use of the thickness gained by the previous joseki, and while it does push black toward's white's joseki, there is really no chance of attack, as black can all to easily settle his shape and counter attack.

"C" disregard's D4 and instead looks toward's limiting black's framework in the upper side. While this is a good idea, I would consider it too early. Not however that it is one space to the left of P17. A move at P17 is a sitting duck for an attack. "c" on the other hand, allows a little more room to breath, so to speak, and is not so easily attackable. A joseki would probably follow.]
;W[cn]
;B[nq]
;W[cp]
;B[cq]
;W[dn]LB[co:A][lq:B]C[*note*

This is a tricky, tempting move. If black falls into the trap of playing atari at "a", white will immediately play pincer at "b". This would be disastrous for black, because his O3 stone would be caught in a forceful attack, but he wouldn't be able to respond to it. If he does, white always has the option in the middle of the attack to go back and play the ajii of B4, after which Not only is black's O3 group weak and under attack, but so is his group in the lower left corner. (Black B5, White B3, BLack D3, White D5 sequence), after which, black would have a very tough time winning the game.

Black should instead draw back and play something around F3. This is a litle more active than E3, and offers a little more support for the O3 stone. After which, he still has the Ajii at C5, and white pincer's at "b", black has more options.

*note*

Also, note that D6 forces black to shore up his framework, while at the same time shoring up white's framework.]
;B[fq]LB[lp:B][lq:A]C[A pincer at "a" seems like a good fighting move, but white should be wary of the counter pincer at Q6 or R6. With the R16 stone offering backup support and the F3 group offering backup support, white would be put in a very troubled situation. Yet a strengthening move around R6 would essentially be a bad gote move which would do very little, and which would give black the freedom to play high and develop his framework.

A better move might be at "b", the high pincer, which allows black an easy way out to connect under, and at the same time, allows white to build some high thickness. If black goes for a counter pincer, on the other hand, white will have an easier time staying connected, and the resulting thickness would put pressure on both O3 and the pincer stone.]
;W[lp]C[(See variations)]
;B[pq]
(;W[qq]
;B[no]
(;W[op]
;B[oq]
;W[qp]
;B[np]
;W[pm]C[Very good result for black.])
(;W[oq]
;B[op]
;W[pr]
;B[po]
;W[qo]
;B[pn]
;W[nr]
;B[mq]
;W[mr]
;B[lr]
;W[lq]
;B[kr]C[Good result for black.])
(;W[np]
;B[op]
;W[mp]
;B[oo]
;W[pr]
;B[oq]
;W[qp]
(;B[or]
;W[qn]C[Ok result for black.])
(;B[qn]C[Black is slightly better.])))
(;W[no]
;B[qp]
;W[np]
;B[op]
;W[po]
;B[oo]
;W[mq]
;B[pn]
;W[nr]
;B[oq]
;W[iq]C[Joseki.

The result of this joseki is that black's loose framework in the bottom has been destroyed, and black's bottom right corner group is feeling some pressure.

I'm not sure, but I think black would be wise to add an extra stone in gote to make sure that white can not kill it. A move around B4 would bring some corner profit, although in this game, black should wince having to play there.

At the same time, white does not get a position that is easily built upon at the bottom. Her stones on the bottom side are not very useful, and the right corner, is strong and capable of expanding, so spending a move in gote should be, if not tasty, at least able to swallow. And white should be satisfied that she reduced black's framework AND that she get's another move to prevent black from expanding the right side in sente. So both sides should be satisfied.]
;B[bp]C[*note* White should be fairly happy to give up the C4 stone for a big move on the right side. The C4 stone is not very large. Of course, if she makes a large sente move, she might be able to rescue it later.])))))

http://igokisen.web.fc2.com/13agon1-1.sgf

http://igokisen.web.fc2.com/2007kl176.sgf