(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[6.50]
PW[Baduk]PB[movies]
(;B[dp]C[Hello, My name is Ben Lockhart. I am a Korean Yeonggusaeng (Insei) at Choongam Dojang where I have studied for the past 3 years. This is a quick lecture about endgame. I am just going to go over the super basics of theory, without going into super specific endgame counting involving ko's which leads to 1/3rds and 2/3rds of a point. Then I am going to rip apart the awful endgame of two young Korean Inseis whose game I reviewed.

First off is Gote endgame]
;AW[bn][bo][ap][bp][cp][cq][ar][cr][dr][es]AB[am][bm][cm][an][cn][ao][co][jp][dq][fq][er]LB[es:1]C[The simplest type of endgame move is a Gote with no followup.
This move is worth two points.]
(;W[pd]
;AW[pb][qb][sb][qc][qd][rd][sd][re][rf]AB[la][lb][ob][lc][mc][pc][md][nd][od][pd][qe][se][qf][sf][qg][rg][sg]C[But what about a gote move like this which has a gote follow up? ]PL[W]
;W[oa]
;B[na]
;W[pa]TR[qa][nb]C[so after this it is at least the same two marked points as before but now with a 5 point gote follow up]
;W[nb]
;B[oc]
;W[ma]LB[oa:1]C[The rest of blacks 4 points are gone plus one capture so 5 points total for white.
Does that mean white's original hane is 5+2=7 points? Absolutely not, because black might be the one who gets that 5 point gote move, so in basic go theory it is a 50/50 chance you will get to play the follow-up, so the value is halved. So white's original move at 1 is still worth its full 2 points plus half of a 5 point gote follow-up, therefore it is worth 4.5 points. 

If there was yet another gote follow-up then that would be 1/4th of its value and so on.]
;B[dd]C[Next: Gote moves with Sente follow-ups.]
;AW[ea][ab][cb][db][cc][ad][bd][cd][be][de][ee][bf]AB[ha][eb][hb][dc][gc][hc][fd][gd][ae][ce][af][cf][ag][bg][cg]LB[ea:A]C[This move is worth its two points plus the FULL value of the next move.]PL[B]
;B[jj]C[after black tenukis]
;AW[fb]AB[ec]LB[ea:A][fb:1][ec:2][fc:B]C[White exchanges 1 for 2 which is absolute sente which means it's his guaranteed 4 extra points.
So the value of the move at A is 2+ 4 = 6 points. It's worth a tiny bit more because of the gote move at B for white, But this move is a bigger gote for black so we'll just ignore this because i was too lazy to create a cleaner example.]PL[B]
(;B[pp]C[Now reverse sente.]
;AE[ea][ha][la][ma][oa][pa][ab][cb][db][eb][fb][hb][lb][ob][pb][qb][sb][cc][dc][ec][gc][hc][lc][oc][pc][qc][ad][bd][cd][dd][fd][gd][od][qd][rd][sd][ae][be][ce][de][ee][qe][re][se][af][bf][cf][qf][rf][sf][ag][bg][cg][qg][rg][sg][jj][jp][pp]AW[nc][nd][pd][dq][eq][fq][hq][iq][jq][kq][lq][mq][fr][hr][cs][hs]AB[kb][mb][en][ep][fp][gp][gq][nq][oq][pq][qq][rq][sq][gr][sr][ds][es][gs][ss]C[To understand how to count reverse sente you have to understand the over simplification that goes along with it.

In basic endgame counting reverse sente moves are valued double. The reason for this is that it is assumed the endgame will flow perfectly; there will be a group of 10 point endgames, then 9 points, then 8 points etc.. so here we have a game where there is a three point reverse sente move at the top and two 6 point moves at the bottom. LET US ASSUME THIS IS ALL THAT IS LEFT. ]
(;W[nr]LB[nr:1]C[if I play 1 as white....]
;AW[oa][pb][mr][ns]AB[ma][na][or][fs][os]LB[ma:8][na:6][oa:7][pb:9][mr:5][nr:1][or:2][fs:10][ns:3][os:4]C[Then the game will go like this:

Ive gained my 6 points at the bottom and you've gained 6 plus 3 at the top. so our DIFERRENCE is 3 points.]
;B[jj]
;AE[oa][jj][er][or][ds][es][ns][os]AW[ma][na][lr][fs][ls]AB[la][mr][nr][ms]LB[la:2][ma:1][na:3][lr:5][mr:4][nr:8][fs:9][ls:7][ms:6]C[If instead I start at 1... then I gained 9 points and you gained 6. So our difference is 3 points again but in my favor, which means this move is worth 6 points and in a situation with an even number of equal gote endgames left, playing the reverse sente move is correct endgame as you can see here. It is very important to understand however that this kind of counting is an extreme simplification because...]
;W[cb]
;AE[la][ma][na][pb][hq][iq][jq][kq][lq][mq][nq][oq][pq][qq][rq][sq][hr][lr][mr][nr][sr][fs][hs][ls][ms][ss]AW[ba][ab][db][cc][ad][bd][cd][be][bf]AB[ea][eb][dc][fc][dd][ae][ce][af][cf][ag][bg][cg][er][ds][es]LB[ma:A]C[Obviously in a situation where this is the only endgame left on the board, playing at A is not valued at 6 points any longer. If I play A...]PL[W]
(;W[ma]
(;AW[da][na]AB[la][fs]LB[da:5][ma:1][na:3][fs:4]TR[ca][la][oa][ob]C[Then I've only gained 4 points where as black gains 6 with 4. So remember that doubling reverse sente moves is based on an assumption that the endgame perfectly regular which it never will be. In an actual game you need to factor in the remaining moves and their values, which you can improve at through quick counting practice and experience.]
;B[jj]
;AE[ba][da][ea][la][ma][na][ab][cb][db][eb][kb][mb][nb][cc][dc][fc][mc][nc][ad][bd][cd][dd][md][nd][pd][ae][be][ce][af][bf][cf][ag][bg][cg][jj][am][bm][cm][an][bn][cn][en][ao][co][ap][bp][dp][fp][cq][dq][eq][fq][gq][ar][cr][dr][er][fr][gr][cs][ds][es][fs][gs]AW[in][io][ep][gp][ip][iq][ir]AB[jn][jo][ro][jp][mp][op][qp][jq][jr]C[Lastly is Double sente. If there is a move that is truly double sente and giving Black the marked stones is not aji keshi, then play it, period. It is 4 free points, and free points are what go players live for.

Before I jump into some endgame tesujis and sequences that I'll go over in a game let's do two endgame problems, one easy and one hard. 

here is the first (easy) problem in Lee Chang Ho's endgame book vol1:]
(;W[eq]
;AE[in][jn][bo][io][jo][ro][cp][gp][ip][jp][mp][op][qp][iq][jq][ir][jr]AW[cj][ck][cl][cm][dn][do][cr][dr]AB[dk][dl][dm][em][en][fo][fp][fq][er][fr][ds]C[Can you find it?]
;B[dq]C[The cut here is nice.]
(;W[cq]C[after white plays at 1]
;B[cs]
;W[bs]
;B[es]
;W[br]LB[eo:A][dp:5][br:4][bs:2][cs:1][es:3]C[Black now has a free point at A.

Note the timing of the cut. If black plays 1-4 first the white would ofcourse just respond to the cut at 5.

Now for the hard problem]
(;B[dj]
;AE[cj][dj][ck][dk][dl][cm][dm][em][dn][en][do][ep][cq][dq][br][cr][bs][cs][es]AW[gp][hp][ip][kp][mp][op][qp][fq][er][fr][ds]AB[cl][cn][go][ho][dp][eq][dr]C[Here is a relatively common shape. This is something I was shown years ago that always stuck with me. How should Black play?]PL[B]
(;B[cs]C[Yes it it true that If Black blocks here...]
;W[cr]
;B[es]
;W[cq]
;B[dq]
;W[bs]
;B[ds]
;W[ar]C[White can live. However lets think about the points...]
;B[bq]
;W[bp]
;B[cp]
;W[br]
;B[bo]
;W[aq]
;B[ao]
;W[ap]TR[ao][bo][ap][bp][cp][aq][bq][cq][dq][ar][as]C[White can live. After this how many points has Black lost?

11 marked spaces as opposed the the variation where I pull back at C2 plus 2 points that white makes with his two eyes. We each captured 1 stone so those cancel out. so 13 point in total lost. But how about white?...]
;AB[hr]LB[hr:1]C[1 is the correct endgame tesuji.]PL[W]
;W[gq]
;B[fs]
;W[ir]
;B[is]
;W[js]
;B[hs]
;W[gr]
;B[gs]
;W[jr]
;B[hq]
;W[iq]TR[gq][hq][iq][gr][hr][ir][jr][fs][gs][hs][is][js]C[After Blacks moves white has lost the 12 marked points as opposed to the variation where black plays c2. So white gaines one point, BUT I GAINED SENTE! Sente in the early endgame is of enourmous importance and worth way more than 1 point. Therefore in an actual game....]
;B[ep]
;AE[ao][bo][ap][bp][cp][ep][aq][cq][dq][gq][hq][iq][ar][br][gr][hr][ir][jr][bs][fs][gs][hs][is][js]AW[ds][es]AB[cr]LB[cr:4][cs:2][ds:1][es:3]C[1-4 is best for both.])
(;B[cr]C[If you answered here then you werent thinking about endgame!]))
(;B[eo]))
(;W[dp]C[If white plays here...]
;B[br]C[black has the nose hit tesuji.]))
(;W[js]
;B[ks]
;W[is]
;B[lr]C[If this is not aji keshi for the corner, then play it as fast as you can]))
(;B[la]
;W[na]
;B[fs]
;W[da]))
(;W[fs]C[Better in this case.]
;B[na]
;W[oa]
;B[ma]
;W[ob]
;B[da]))
(;B[na]C[What does reverse sente mean? It means that for one side, in this case black, there is a sente move.
And for the other side there is only gote. 

Reverse sente is playing the gote move so your opponent can not play the sente move.]
;W[oa]
;B[ma]
;W[ob])
(;W[ma]
;B[la]
;W[na]))
(;AE[fb][ec]C[Again, let's break it down.]
;B[fb]LB[ga:4][gb:3][ec:1][fc:2]C[If black were to play here first..Black has 4 points.]
;W[pp]
;B[fa]LB[fa:A][ga:4][gb:3][ec:1][fc:2]C[The 4th point at number 4 we can assume will be black's, because playing at A is more 'interesting' for black than for white. ])
(;W[fc]C[If white plays here, it is a 1 point gote move.]
;B[ed]
;W[fa]C[White takes gote, because he needs to defend here.])
(;B[fc]C[If black plays here, it is also 1 point, but black has a GOTE FOLLOW UP. So we need to devide that follow up by two and add it to the 1 point.]
;W[pp]
;B[fa]
;W[da]
;B[gb]LB[fc:A]C[Black gained 3 points in this follow up. Therefore His original move at A is worth 1 + 1.5 = 2.5 points.
So the chance is bigger that black will play here, since it's bigger for black than for white.]))
(;B[fs]
;W[ds]LB[cs:1][fs:2]C[To understand endgame moves, you must realize that endgame moves usually do two things:
1. Enlarge your own territory
2. Reduce your opponent's territory.

By playing endgame here, white has gained 1 point and he also destroyed 1 point of black.

We can come to this conclusion when we always compare the situations from white playing the endgame or black playing it.])
(;AE[es]
;B[ds]C[When black plays the endgame move..]
;W[cs]
;B[es]LB[cs:B][fs:A]C[Black has a point at A and white no longer has a point at B.]))
(;B[qd]C[This is a game between two Korean Inseis.]
;W[dd]
;B[pq]
;W[dp]
;B[oc]
;W[po]
;B[qo]
;W[qn]
;B[qp]
;W[rd]
;B[qe]
;W[pm]
;B[nq]
;W[qi]
;B[cj]
;W[cl]
;B[cf]
;W[fc]
;B[bd]
;W[ch]
;B[ef]
;W[di]
;B[cc]
;W[ic]
;B[dj]
;W[fi]
;B[ej]
;W[fg]
;B[el]
;W[cn]
;B[gk]
;W[re]
;B[rc]
;W[qf]
;B[pf]
;W[qg]
;B[kc]
;W[dc]
;B[dr]
;W[dq]
;B[er]
;W[cr]
;B[hq]
;W[cb]
;B[bb]
;W[cd]
;B[bc]
;W[jq]
;B[lq]
;W[ff]
;B[jo]
;W[db]
;B[ba]
;W[fq]
;B[fr]
;W[ip]
;B[fp]
;W[io]
;B[cq]
;W[bq]
;B[cs]
;W[br]
;B[eq]
;W[jn]
;B[nl]
;W[pp]
;B[op]
;W[rn]
;B[oo]
;W[pn]C[The first endgame move we will discuss comes here. This is a common enough shape that you should have it memorized, Black to play in the corner.]
(;B[sp]C[This is the correct move.]
(;W[pe]
;B[pd]
;W[oe]
;B[md]C[At this exact moment white has an endgame tesuji to gain points.]
;W[qc]C[Cutting here is nice.]
(;B[qb]C[After black plays here in the actual game...]
;W[sc]C[White gets the nice atari and gains.]
;B[rb]LB[od:A]C[The tesuji made sure white can give atari at A in endgame.]
;W[kb]
;B[lb]
;W[fo]
;B[go]
;W[gn]
;B[eo]
;W[fn]
;B[do]
;W[cp]
;B[dm]
;W[gp]
;B[gq]
;W[ep]
;B[hp]
;W[co]
;B[em]
;W[ho]
;B[gp]
;W[ir]
;B[hm]
;W[hn]
;B[hr]
;W[jl]
;B[im]
;W[jm]
;B[ko]
;W[hl]
;B[il]
;W[ik]
;B[gm]
;W[in]
;B[gi]
;W[ll]
;B[gh]
;W[fh]
;B[ij]
;W[jj]
;B[hk]
;W[ii]
;B[jk]
;W[kk]
;B[ik]
;W[ji]
;B[hi]
;W[fj]
;B[gj]
;W[nm]
;B[mg]
;W[og]
;B[mi]
;W[bh]
;B[bf]
;W[ol]
;B[dg]
;W[bk]
;B[bj]
;W[dh]
;B[ee]
;W[fk]
;B[ek]
;W[fl]
;B[fm]
;W[hf]
;B[jb]
;W[ib]
;B[nk]
;W[gl]
;B[ih]
;W[mj]
;B[nj]
;W[ni]
;B[nh]
;W[oi]
;B[lj]
;W[mk]
;B[ml]
;W[lk]
;B[mm]
;W[li]
;B[mh]
;W[jg]
;B[ig]
;W[if]
;B[jh]
;W[kh]
;B[kg]
;W[jf]
;B[lh]
;W[kj]
;B[ki]
;W[lm]
;B[mn]
;W[kh]
;B[ei]
;W[eh]
;B[ki]
;W[kr]
;B[lj]
;W[is]
;B[lr]
;W[ks]
;B[pj]
;W[pk]
;B[pi]
;W[oh]
;B[oj]
;W[qj]
;B[fe]
;W[hg]
;B[hh]
;W[ro]
;B[rp]
;W[nn]
;B[on]
;W[om]
;B[no]
;W[ge]C[We are now in the endgame. In the actual game Black played an awful endgame and lost by 4.5.

Right now is when you should be looking for victory! The endgame is about taking, It's about exploiting shapes for one point gains, You have sente. Where do you play?]
;B[qk]C[You cut here! We found this move after about 10 minutes and the variations are what the endagme is all about baby!]
(;W[rj]C[So white has to play here. REMEMBER we are looking for any way to gain even one point. One point is NOT small. Many people play the endgame in a way where they feel everthing will basically even out anyway and they rush through it. NONSENSE! seize your own victory through endgame gains, study it as you study any other part of the game.]
;B[ql]LB[sn:B][so:A]C[starting here is obvious enough. when reading this kind of manuever you should always remember that if white CAN'T block at B after Black A, then you've already gained at least one point.]
;W[sm]C[White's strongest response is here]
(;B[rm]C[Black should play here]
(;W[rl]
;B[so]C[Black now plays here.]
(;W[qm]LB[sn:A]C[So white must play here. Its really important to understand that this is a one point gain! A is dame where as r7 is white playing INSIDE his own teritory.]
;B[ok]
;W[rk]C[This is best for both.]
;B[ph]
;W[pg]
;B[ln]
;W[kn]
;B[ls]
;W[ia]
;B[jc]
;W[jd]
;B[kd]
;W[ke]
;B[le]
;W[cm]
;B[kf]
;W[ce]
;B[be]
;W[je]C[The upper left corner looked something like this. Can you spot the endgame tesuji? they sure didn't.]
;B[ca]
;W[da]
;B[fd]
;W[gd]
;B[ec]C[If you found this move, pat yourself on the back]
(;W[fb]
;B[ed]
;W[eb]C[best for both again. and a two point gain for black.

The point is this:

 In a game where players constantly lose by 2.5 or 3.5 or a half point, dan players are insanely reckless about the endgame, Let's say I win this game by 1.5 as Black, well then this tesuji WON ME THE GAME. In the same way that killing a group can win you the game. Don't sleep on endgame people, study it.


])
(;W[ed]C[If white plays here]
;B[fb]C[this atari ends the game]
;W[eb]
;B[gc]C[again a picnic ko emerges]))
(;W[sn]C[If white blocks...]
;B[ph]
;W[pg]
;B[qh]
;W[rh]
;B[rk]
;W[qm]
;B[sj]
;W[ri]
;B[sl]C[A massive picnic Ko]))
(;W[sl]C[If white extends...]
;B[ok]
;W[pl]
;B[sn]
;W[so]
;B[qm]C[game over])
(;W[rk]C[This move works too]
;B[so]
;W[rl]
;B[sn]
;W[qm]LB[pg:B][ph:A][qh:C][rh:D][ln:E][lo:F]TR[ok]C[This essentially reverts HOWEVER blacks liberty isnt filled so later after ABCD when white plays E black can block at F so it is much worse for white.]))
(;B[so]C[If black just plays here ]
;W[sn]C[White blocks and black hasn't gained anything more]))
(;W[rk]C[This is not good]
;B[rg]C[BOOM! This tesuji you find in books but rarely occurs in actual games, but here it is in all its glory.]
(;W[rf]C[If white plays here we can see what will happen]
;B[ph]
;W[pg]
;B[qh]C[White collapses])
(;W[rh]C[if white plays here?]
;B[rf]LB[se:A][pg:B]C[black cuts and A and B are miai])))
(;B[sd]
;W[rf]LB[qb:C][sd:A][rf:B]C[Note that if A for B was already exchanged, the cut is meaningless as black just plays C])
(;B[rb]LB[qb:C][sd:A][rf:B]C[playing here is not better. First of all it leaves more aji but also even if black gets to play at A, white will just answer at B having already gained the endgame at C for later.]
;AB[sd]
;W[rf]
;B[]
;W[qb]
;B[pb]
(;W[sb]C[This move is the correct tesuji,]
;B[pc]
;W[se]C[Later white can play this 5 point endgame sequence. so Black hasnt really gained anything.])
(;W[se]C[if white blocks here instead...]
;B[sb]C[black will occupy the vital point.])))
(;W[qq]
;B[rq]
;W[qr]
;B[rr]
;W[pr]
;B[oq]
;W[ro]
;B[rp]C[Now perhaps you can see the brilliance of T4. Notice that black does not need to play another move.]
;W[rs]LB[rs:1]C[If white 1]
;B[sr]LB[sr:2][rs:1]C[Black simply plays 2. ]))
(;B[so]C[If black plays here then after white cuts]
;W[qq]
;B[rq]
;W[qr]
;B[rr]
;W[pr]
;B[oq]
;W[ro]
;B[rp]
;W[sp]C[Later white can throw in here. Black can do better.])
(;B[rp]C[This reverts]
;W[qq]
(;B[rq]
;W[qr]
;B[rr]
;W[pr]
;B[oq]
;W[sp]C[again White can play at the vital point/])
(;B[qr]
;W[rq]
;B[rr]
;W[so]C[If Black plays like this then once again he will have to play in his own territory. Therefor...]))))