(;AB[cr]AB[dr]AB[dq]AB[dp]AB[ep]AB[fp]AB[gp]AB[gq]AB[gr]AW[hr]AW[hq]AW[hp]AW[go]AW[fo]AW[eo]AW[do]AW[co]AW[cp]AW[cq]AW[br]AW[cs]C[White plays C1. Is your door shape dead?]LB[cm:Tenuki]AW[hs]AP[goproblems] (;B[bq];W[as]C[A brilliant tesuji! But what happens when white is skilled in tesuji as well?] (;B[ds];W[gs]C[So, a ko fight is it? Do your best.] (;B[bs];W[js]LB[ks:R]C[R to respond to white's threat. All threats are worth 20 points.] (;B[ks];W[cs]LB[cm:T]C[Play T for an external threat.] (;B[fs];W[er];B[bs];W[jr]LB[kr:R] (;B[kr];W[cs]LB[cm:T] (;B[fr];W[eq];B[bs];W[jq]LB[kq:R] (;B[kq];W[cs]LB[cm:T] (;B[bp];W[bo];B[bs];W[jp]LB[kp:R] (;B[kp];W[cs]LB[cm:T] (;B[aq];W[ao];B[bs];W[jo]LB[ko:R] (;B[ar];W[ko]C[Congratulations! You played that perfectly!CHOICERIGHT]) (;B[ko];W[cs]C[No threat is large enough to stop white from killing this big group.])) (;B[cm];W[ap]C[No threat is large enough to stop white from killing this big group.]) (;B[ap];W[ao]C[Ouch, black is dead.]) (;B[ao];W[aq]C[No threat is large enough to stop white from killing this big group.])) (;B[ar]C[];W[kp]C[Alive, but you didn't need to let white use that threat.])) (;B[cm];W[bp]C[There are still internal threats to play.]) (;B[aq];W[bp]C[Black now has less internal threats than he would have had with correct play.])) (;B[ar];W[kq]C[Alive, but there was no need to let white use that threat.])) (;B[cm]C[There are still internal threats to play.]) (;B[eq];W[fr]C[This move is inferior, giving white an atari and black less internal threats later.]) (;B[bp];W[bo];B[bs];W[jq]LB[kq:R] (;B[kq];W[cs]LB[cm:T] (;B[fr];W[eq];B[bs];W[jp]LB[kp:R] (;B[kp];W[cs]LB[cm:T] (;B[aq];W[ao];B[bs];W[jo]LB[ko:R] (;B[ar];W[ko]C[Congratulations! You played that perfectly!CHOICERIGHT]) (;B[ko];W[cs]C[No threat is large enough to stop white from killing this big group.])) (;B[cm];W[ap]C[No threat is large enough to stop white from killing this big group.]) (;B[ap];W[ao]C[Ouch, black is dead.]) (;B[ao];W[aq]C[No threat is large enough to stop white from killing this big group.])) (;B[ar]C[];W[kp]C[Alive, but you didn't need to let white use that threat.])) (;B[eq];W[fr]C[This move is inferior, unnecisarily giving white an atari.]) (;B[cm]C[There are still internal threats to play.])) (;B[ar];W[kq]C[Alive, but there was no need to let white use that threat.]))) (;B[ar];W[kr]C[Alive, but there was no need to let white use that threat.])) (;B[cm]C[There are still internal threats to play.]) (;B[fr];W[fs]C[This is inferior, even if black lives, he will have less points]) (;B[bp];W[bo];B[bs];W[jr]LB[kr:R] (;B[ar]C[Alive, but there was no need to let white use that threat.]) (;B[kr];W[cs]LB[cm:T] (;B[fs];W[er];B[bs];W[jq]LB[kq:R] (;B[kq];W[cs]LB[cm:T] (;B[fr];W[eq]) (;B[eq];W[fr]C[This move is inferior, unnecisarily giving white an atari.]) (;B[cm]C[There are still internal threats to play.])) (;B[ar];W[kq]C[Alive, but there was no need to let white use that threat.])) (;B[fr];W[fs]C[This move is slightly inferior, as even if black lives, he will have less territory.]) (;B[aq];W[ao];B[bs];W[jq]LB[kq:R] (;B[kq];W[cs] (;B[fs];W[er];B[bs];W[jp]LB[kp:R] (;B[kp];W[cs]LB[cm:T] (;B[fr];W[eq];B[bs];W[jo]LB[ko:R] (;B[ar];W[ko]C[Congratulations! You played that perfectly!CHOICERIGHT]) (;B[ko];W[cs]C[No threat is large enough to stop white from killing this big group.])) (;B[eq];W[fr]C[This move is inferior, as even if black lives, he has unnecisarily given white an atari.]) (;B[cm]C[There are still internal threats to play.])) (;B[ar];W[kp]C[Alive, but there was no need to let white use that threat.])) (;B[fr];W[fs]C[This move is slightly inferior, as even if black lives, he gets less territory.])) (;B[ar]C[];W[kq]C[Alive, but there was no need to let white use that threat (and now white has f2)]) (;B[fs]C[I am not inputting the variations for this right now...NOTTHIS])) (;B[cm]C[There are still internal threats to play.])))) (;B[ar]C[];W[ks]C[Alive, but there was no need to let white use that threat.]) (;B[fs];W[ks]C[Alive, but there was no need to let white use that threat.])) (;B[fs]C[Maybe you'd like to take the ko before using your threats?]) (;B[fr]C[Maybe you'd like to take the ko before using your threats?]) (;B[bp]C[Maybe you'd like to take the ko before using your threats?]) (;B[aq]C[Maybe you'd like to take the ko before using your threats?])) (;B[er];W[ds] (;B[es];W[gs];B[bs];W[cs]C[Black is dead]) (;B[fq];W[fs] (;B[gs];W[es];B[fr];W[eq]C[Ouch]) (;B[es];W[gs];B[bs];W[cs]C[Black is dead])) (;B[fs];W[fq]C[Black is dead]) (;B[gs];W[fq] (;B[es];W[fr];B[bs];W[cs]C[Black is dead]) (;B[fr];W[es];B[fs];W[eq]C[Ouch.]))) (;B[fr];W[gs] (;B[ds]C[A ko, but you've already used a threat.]) (;B[fs];W[ds] (;B[es];W[eq];B[bs];W[cs]C[Black is dead]) (;B[eq];W[es];B[er];W[fq]C[Ouch.])) (;B[eq];W[es];B[ds];W[fs]C[A ko, but you've already wasted some threats.])) (;B[gs];W[ds];B[es];W[fr];B[bs];W[cs]C[Black is dead])) (;B[er];W[ds] (;B[fq];W[fs] (;B[es];W[gs];B[bs];W[cs]C[Black is dead.]) (;B[gs];W[es]C[Black is dead])) (;B[fs];W[fq]C[Black is dead]) (;B[es];W[gs] (;B[bq];W[as];B[bs];W[cs]C[Black is dead]) (;B[bs];W[cs]C[Black is dead])) (;B[gs];W[fq] (;B[es];W[fr];B[bq];W[as];B[bs];W[cs]C[Black is dead]) (;B[fr];W[es]C[Black is dead]))) (;B[cm]C[Actually, there's something you could have done.]) (;B[fr];W[gs] (;B[eq];W[es] (;B[ds];W[fs]C[Black is dead]) (;B[fs];W[ds]C[Black is dead])) (;B[bq];W[as] (;B[ds]C[A ko, but you've already used a threat.]) (;B[fs];W[ds] (;B[es];W[eq];B[bs];W[cs]C[Black is dead]) (;B[eq];W[es];B[er];W[fq]C[Ouch.])) (;B[eq];W[es];B[ds];W[fs]C[A ko, but you've already wasted some threats.])) (;B[fs];W[eq] (;B[ds];W[er]C[Black is dead]) (;B[er];W[ds]C[Black is dead]) (;B[bq];W[bp];B[ds];W[er]C[Black is dead])) (;B[es];W[eq]C[Black is dead]) (;B[ds];W[fs]C[Black is dead])) (;B[gs];W[ds] (;B[es];W[fr];B[bq];W[as];B[bs];W[cs]C[Black is dead]) (;B[er];W[fq] (;B[es];W[fr];B[bq];W[as]) (;B[fr];W[es]C[Black is dead]))) (;B[ds];W[gs] (;B[fs];W[er]C[Black is dead]) (;B[fr];W[fs]C[Black is dead])))