Problem	2220
Created	2003-05-12
Source
Rating

Difficulty	12 kyu
Average Solve Time	54 secs
User Attempts	1896 / 5360
Solve Ratio Rating	5 kyu
	rating history

This is my first 7x7 game. If you could not find the solution, then you can play A to read the idea behind this problem.

(;GM[1]FF[4]CA[UTF-8]AP[CGoban:2]ST[2] RU[Japanese]SZ[7]KM[0.00] PW[White]PB[Black] ;AW[bb][eb][bc][cc][dc][ec][fc][cd][ed][ce][ee][df][ff]AB[ba][ea][ga][ab][cb][db][fb][ac][gc][bd][ae][ge][af][gf][bg][eg][fg]LB[da:A]C[black to kill white] (;B[be]CR[be] ;W[dg]CR[dg]C[Now the best black can do is seki.] (;B[cf]CR[cf] ;W[cg]LB[bf:A]CR[cg]C[A is forced] ;B[bf]CR[bf] ;W[fd]LB[gd:A]CR[fd]C[Please convice yourself A is forced.] ;B[gd]CR[gd] ;W[ef]LB[dd:B][de:A]CR[ef]C[Please convice yourself A or B is forced and play at A.] ;B[de]CR[de] ;W[gg]CR[gg] ;B[fg]CR[fg] ;W[eg]CR[eg]C[seki]) (;B[cg]CR[cg] ;W[cf]LB[bf:A]CR[cf]C[Please follow A to reach seki. Other lines of play are at best seki, too.] ;B[bf]CR[bf] ;W[fd]LB[gd:A]CR[fd] ;B[gd]CR[gd] ;W[ef]LB[de:A]CR[ef] ;B[de]CR[de] ;W[gg]LB[fg:A]CR[gg] ;B[fg]CR[fg] ;W[eg]CR[eg]C[seki])) (;B[bf]CR[bf] ;W[dg]LB[gd:B][be:A]CR[dg]C[Now black collapses. Follow A or B to see why.] (;B[be]CR[be] ;W[fd]LB[gd:A]CR[fd] ;B[gd]CR[gd] ;W[ef]LB[cf:A]CR[ef] ;B[cf]CR[cf] ;W[fe]LB[cg:A]CR[fe] ;B[cg]CR[cg] ;W[gg]LB[fg:A]CR[gg] ;B[fg]CR[fg] ;W[eg]LB[de:A]CR[eg] ;B[de]CR[de] ;W[gg]CR[gg]C[black has no ko threat.]) (;B[gd]CR[gd] ;W[ef]LB[gb:A]CR[ef] ;B[gb]CR[gb] ;W[fe]LB[fa:A]CR[fe] ;B[fa]CR[fa] ;W[fd]LB[da:A]CR[fd] ;B[da]CR[da] ;W[gg]LB[fg:A]CR[gg] ;B[fg]CR[fg] ;W[eg]LB[ca:A]CR[eg] ;B[ca]CR[ca] ;W[gg]LB[aa:A]CR[gg] ;B[aa]CR[aa] ;W[ad]CR[ad]C[black collapses.])) (;B[cf]CR[cf] ;W[be]LB[ad:A]CR[be]C[A is forced.] ;B[ad]CR[ad] ;W[bf]LB[dg:A]CR[bf]C[The best black can do is A.] ;B[dg]CR[dg] ;W[cg]CR[cg]C[black has no ko threat.]) (;B[cg]CR[cg] ;W[dg]LB[be:A]CR[dg]C[Now the best black can do is seki. Please follow A.] ;B[be]CR[be] ;W[cf]LB[bf:A]CR[cf] ;B[bf]CR[bf] ;W[fd]LB[gd:A]CR[fd] ;B[gd]CR[gd] ;W[ef]LB[de:A]CR[ef] ;B[de]CR[de] ;W[gg]LB[fg:A]CR[gg] ;B[fg]CR[fg] ;W[eg]CR[eg]C[seki]) (;B[dg]CR[dg] ;W[bf]CR[bf] (;B[be]CR[be] ;W[cf]CR[cf] ;B[cg]CR[cg] ;W[fd]CR[fd] ;B[gd]CR[gd]C[RIGHT White is dead.]) (;B[cg]CR[cg] ;W[be]CR[be] ;B[ad]CR[ad] ;W[fd]CR[fd] ;B[gd]CR[gd]C[RIGHT White is dead.])) (;B[ef]CR[ef] ;W[dg]LB[fe:A]CR[dg]C[A is forced. If white got to play A black loese.] ;B[fe]CR[fe] ;W[be]LB[ad:A]CR[be]C[A is forced.] ;B[ad]CR[ad] ;W[bf]CR[bf]C[Black has two eyes but its right groups can't connect to the eyes.]) (;B[fe]CR[fe] ;W[dg]LB[ef:A]CR[dg]C[A is forced. If white got to play A black loses.] ;B[ef]CR[ef] ;W[be]LB[ad:A]CR[be]C[A is forced.] ;B[ad]CR[ad] ;W[bf]CR[bf]C[Black get two eyes but its right groups can't connect to the eyes.]) (;B[de]CR[de] ;W[dg]CR[dg]C[Now the best black can do is seki. Use the navirgator to see how to reach seki in other variations.]) (;B[dd]CR[dd] ;W[dg]CR[dg]C[Now the best black can do is seki. Use navirgator to see how to reach seki in other variations.]) (;B[da]CR[da]C[White has one true eye and black has several false eyes. But if black can connect its false eyes in a loop, then black can kill white.]) (;B[gd]CR[gd] ;W[dg]CR[dg]C[Now the best black can do is seki. Use the navigator to see how to reach seki in other variations.]))