(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.00]
PW[White]PB[Black]CR[hs]AW[km][lm][mm][nm][om][pm][qm][rm][sm][kn][ko][kp][kq][kr]AB[am][bm][cm][dm][em][fm][gm][hm][im][jm][cn][en][gn][in][jn][jo][jp][jq]LB[gq:B][hq:C][iq:A][jq:D][fr:E][gr:F]TR[hr][jr][gs][is][js]SQ[ir]C[This file is a demonstration of the values of the monkey jump in several situations. Keep in mind that this analysis is only relative to undercutting a strong group that has no chance of dying or getting cut.


Starting position #1. This is the worst case for black. he has no stones to suport him in the defense of the monkey jump. 

The monkey jump is worth around 16  points in this case.

The quick summary of the other possible situations is that if black had a stone at A it would only be worth 6 points in sente (12 points effectively) if black has a stone at A and B, Eor F, the monkey jump is 5 points in gote for white. A stone at C has NO EFFECT on the outcome of the monkey jump. The ABSENCE of a stone at D has a 1 point reduction of the value of the monkey jump in all these cases  removing makes black's defense one point weaker. Since that point is already lost it cannot be factored into the importance of defending (or not attacking/not attacking for white) and removing D makes the area less important by one point.

If black has a stone at any of the marked intersections, or if D is absent from this diagram. triangles, the situation is not a monkey jump situation. The monkey jump is an extension to the circled intersection. a white play at the square is also very strong, but not considered in this analysis since it is not a monkey jump.]
(;B[jr]C[If there are no bigger moves on the board, black should protect like this, but how big is bigger? about 16 points... see the variations for explanation]
;W[js]
;B[is]
;W[ks]
;B[ir]C[black prevents the monkey jump Score: black 48 white 48.])
(;B[jd]C[If black falis to defend... ]
(;AE[sm]AW[rl][sl]AB[iq]C[Starting position 2: black has a stone at J 3 ]
(;W[]
(;B[jr]C[black should block like this]
;W[ks]
;B[js]C[white 49 Black 49])
(;AW[sm]AB[hq]C[Starting position 3. black has a stone at h3]
(;B[jr]
;W[ks]
;B[js]C[black 48 white 48 if black defends])
(;B[id]
(;AE[hq]AB[gq]C[Starting position 4. White has stones at j3 and g3]
(;W[sk]
(;B[jr]
;W[ks]
;B[js]C[Black  48 White 48 if black defends])
(;AE[jq]C[Starting position 5 black has j3 but not k3]
;B[jr]
;W[jq]
;B[ir]
(;W[ks]
;B[js]C[White 48 Black 47

All of the preceeding variations except the first (Ideal) monkey jump play out exactly the same,  except black's expected value if he defends is one less.  Black gets the same scores in the end, but since he is starting from a worse position, the net cost of each of the previous variations is one less.

The case where black has none of k3 j3 or g3  is not really a monkey jump situation.])
(;W[js]
;B[is]
;W[ks]C[White could play this, but it is gote.])))
(;W[hs]
;B[hr]
;W[is]
;B[gs]
;W[js]C[This is the normal sequence. 
White now ends in Gote.

Black 43  white 48 

The monkey jump here is only worth 5 points]))
(;W[hs]
(;B[is]
;W[ir]
;B[hr]
;W[js]
;B[gs]
(;W[is]
;B[jr]
;W[ks]
;B[gr]C[White ends in sente 

The score is black 42, white 48. 

6 points in sente is worth 12 points. The presence of a stone at h3 has NO EFFECT on the value of the monkey jump.])
(;W[gr]C[white cannot start the ko.]
;B[is]))
(;B[hr]
;W[is]
;B[gs]
;W[js]
;B[gr]C[White ends in sente 

The score is black 42, white 48. 

6 points in sente is worth 12 points. The presence of a stone at h3 has NO EFFECT on the value of the monkey jump.])))))
(;W[hs]
(;B[hr]C[This is the standard defense]
(;W[is]
;B[gs]
(;W[js]
;B[gr]C[This is the normal result  although white wil usually omit the final move and take sente. We can assume that sente is worth at least 1 point, and probably worth 5 or 6 points until very late in the game (or take some other point instead).

black 43 white 49 White makes 6 points in sente.

Sente usually counts as almost double so we can say that this is almost 12 points.])
(;W[jr]
;B[gr]C[Some players play this, but it is poor style. black wil now have j2 as a ko threat, or as his option since it is 1 point gote for white to play j2.  It looks like white can make an extra point but unless black is very careless in the end game white will never get the point. White is better off not leaving this threat.]))
(;W[gs]C[This does not work becaus j3 protects the cut]
;B[is]C[The ability to cut white off makes j3 the MOST IMPORTANT stone in assessing the value of the monkey jump. If J3 is not in place the monkey jump is a disaster.
]
;W[fr]
;B[dr]
;W[eq]
;B[dq]C[White cannot live inside the enormous space inside of this group is quite contrived so I will not consider the chances of living in the corner by sacrificing h2]))
(;B[is]C[This is dangerous and exposes black to a ko.]
;W[ir]
;B[hr]
;W[js]
;B[gs]
(;W[is]
;B[gr])
(;W[gr]
;B[is]
;W[jr]
(;B[hs]
;W[hq])
(;B[hq]
;W[hs]C[White gets a beautiful ko this way. White can loose only a few points for black, loosing is a disaster
]
;B[id]
(;W[md]
;B[is]
;W[nd]
;B[hs]C[If black wins the score is
black 44 white 50 black has lost 6 points and ignored a ko threat])
(;W[is]C[if black looses the ko it is a disaster.]
;B[fr]
;W[fs]
;B[er]
;W[gq]
(;B[gp]
;W[fq]
;B[ep]
;W[eq]
;B[dq]
;W[dr]
;B[cr]
;W[es]
;B[cq])
(;B[es]
;W[gs]
;B[fp]
;W[fq]
;B[eq]
;W[gp]
;B[go]
;W[hp]
;B[ho]
;W[ip])))))))
(;W[hs]C[White gets a perfect monkey jump This stone looks like an overplay but it cannot be killed. 
]
(;B[ir]C[Except in special situations this is usually the best defense.]
;W[is]
;B[js]
;W[jr]
;B[hr]
;W[gs]
;B[fr]
;W[fs]
;B[es]
;W[ks]
;B[gr]
;W[js]
;B[er]C[black 40 white 48 

8 points in sente  (about 16 points.)])
(;B[hr]C[This move is correct in other positions where black has some stones on the 3rd line to help, but doesn't work very well here]
;W[gs]C[White's move looks impossible but black can't stop it. Many a beginner has wondered if white isn't cheating somehow when they se white do this and get away with it.]
;B[is]
;W[ir]
;B[gr]
;W[fs]
;B[er]
(;W[iq]C[This only works if there is space above]
;B[fr]
;W[js]
(;B[hp]
;W[hq]
;B[gq]
;W[ip]C[white would probably take sente here since the atari at h4 is only worth 4-5 points. there are probably bigger moves on the board now, but black either needs to spend a move later or white will come back to this so we will continue.]
;B[io]C[w ends in sente, ]
;W[od]
;B[es]C[black will probably get these moves since they have a high threat value and continuation is gote for white.]
;W[is]
;B[jr]
;W[ks]C[black 34 white 48 

Cost to black: 14 points. Since white ended in sente white probably also got the next biggest move. Sente is usually considered double value, except with really large moves ike this that's sometimes not true since the next move isn't of equal value. We can safely say however that white probably makes at least 25 points out of this.])
(;B[es]
;W[is]
;B[hp]
;W[hq]
;B[gq]
;W[ip]
;B[io]C[w ends in sente ]
;W[pd]
;B[jr]
;W[ks]C[again black 34, white 48 

Cost: 14 points to black]))
(;AW[lp]AB[ip]
;W[jr]
;B[es]
;W[js]
;B[fr]
;W[is]
;B[iq]C[if extending up is not possible 
Black 38 White 48

Cost to Black: 10 points]))
(;B[gr]C[This move leads to disaster. it is too soft. Variations shown here are not the only posibilities, but give you an idea of what happens.]
(;W[gs]
(;B[fr]
;W[fs]
;B[dr]
;W[es]
;B[ds]
;W[er]
;B[eq]
;W[ir]
(;B[jr]C[black cannot do this.]
;W[js]
;B[iq]
;W[hr]
(;B[gq]
;W[hq]
;B[hp]
;W[gp]
;B[fq]
;W[dq]
;B[cq]
;W[dp]
;B[cr]
;W[ep])
(;B[hq]
;W[fq]
;B[gq]
;W[dq]
;B[ep]
;W[cr]C[disaster]))
(;B[hq]
(;W[jr])
(;W[hr]
;B[fq]
;W[iq]
;B[ip]
;W[jr])))
(;B[fs]C[This does not work]
;W[fr]
;B[is]
;W[hr]
;B[ir]
;W[gq]
;B[ds]
;W[er]
;B[dr]
;W[es]C[Disaster. White lives inside with no counterplay for black.])
(;B[ir]
;W[fr]
;B[is]
;W[dr]
;B[hr]
;W[fs]
;B[eq]
;W[er]
;B[cr]
;W[cq]
;B[br]
;W[bq]
;B[dq]
;W[cs]
;B[ar]
;W[aq]
;B[cp]
;W[bs]
;B[bp]
;W[as]
;B[fq]C[Disaster])
(;B[er]
;W[fr]
;B[fq]
;W[fs]
;B[eq]
;W[hr]
;B[gq]
;W[hq]
;B[hp]
;W[es]
(;B[ds]
;W[dr]
;B[jr]
;W[js])
(;B[dr]
;W[ds]
;B[cr]
;W[cs]
;B[br]
;W[bs]
;B[ar]
;W[jr]
;B[ir]
;W[iq]
;B[ip]
;W[is])))
(;W[hr]
;B[hq]
;W[gs]
;B[ir]
;W[gq]
;B[is]
;W[fr]
;B[eq]
;W[er]
;B[fq]
;W[dq]C[disaster
]))
(;B[gs]C[In some situations this is a good defense for black. The key factor is how high is the ceiling. The situation shown here where white can extend a long way vertically, this is bad. but if the wall of stones were at the 4th line, or lower, this is a reasonable play.

The value is situational you must read this one yourself based on the height of the black area that is being invaded.]
(;W[hr]
;B[gr]
;W[hq]
;B[gq]C[White can continue extending upwards, so the defense play at g1 is good when the "ceiling" is low.  This play must be evaluated on a case by case basis. As shown here it is very bad.]
;W[hp]
;B[gp]
;W[jr]
;B[ho]
;W[od]
;B[iq]
;W[ir]
;B[ip]C[black 37 white 51 

14 points in sente... (huge)])
(;W[ir]
;B[jr]
;W[js]
;B[hr]C[black risks a ko]
;W[is]
;B[iq]
;W[ks]
;B[gq])
(;AW[ln]AB[hp]C[with a stone at h4 or h3 this play at g1 becomes useful]
(;W[ir]C[This or K2 are the only moves now for white
]
;B[hr]
(;W[is]
;B[gr]C[b can avoid the ko  this way]
;W[iq]
;B[hq]
;W[oe]
;B[jr]
;W[js]
;B[ip]
;W[ks]C[B 40 w 48 w gets 8 points in sente (16 point value)])
(;W[js]
;B[gr]
;W[iq]
;B[is]
;W[jr]
;B[hq]C[black 39 white 48 w is up 9 points in sente (18 point value)])
(;W[gr]C[w can cause a ko this way]
;B[is]
;W[hq]
(;B[iq]
;W[hs]C[B now needs a ko threat])
(;B[hs]
;W[js]C[disaster])
(;B[fr]
;W[hs]C[B must fight a ko.])))
(;W[hr]C[This ends in gote for white. Gote from the monkey jump is almost always a bad result.]
;B[gr]
(;W[hq]C[white can't play this because it ends in gote.]
;B[gq]
;W[js]
;B[is]
;W[ir]
;B[jr]
;W[ks]
;B[iq]
;W[is]C[white 47 black 40 7 points in gote... not good enough for white.])
(;W[jr]C[This is gote as well
]
;B[hq]
;W[ir])
(;W[ir]C[This is also gote]
;B[jr]
;W[js]
;B[hq]
;W[ks]
;B[iq]
;W[is])
(;W[js]C[also gote]
;B[hq]
;W[is])))))))
