(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.00]
PW[White]PB[Black]
;B[pd]
;W[qf]
;B[nc]
;W[rd]
;B[qc]
(;W[qi]C[Many of you will recognise this position, which comes from one of the most basic joseki patterns in go. In this episode we will discuss whites base, its benefits and weaknesses: what sort of aji can black still expect to exploit from this classic white shape and what kind of black moves are good in which positions?

Let's go!]
(;LB[qg:D][ph:B][rh:E][oj:C][pj:A]C[Depending on the surroundings and the overall board position black has all sorts of aji moves from A to E. These different techniques have different objectives, ranging from pressing white down and making moyo to attacking the base itself. ])
(;B[pj]C[This move is called the "shoulder hit". This technique is especially useful for pressing down a larger formation of your opponent, which in this case would be on the right side. It aims at reducing. ]
;AE[pj]AW[jp][qp][oq]LB[oi:A][pk:B]C[For example, imagine White has more stones on the right and lower side. He is threatening to create a large moyo if he gets the chance jump at A or simply defend his right side in a more solid way, like B.

]
(;W[oi]C[Good for White. ])
(;W[pk]C[Good for White. ])
(;B[pj]LB[pi:1][qi:A][qj:2]C[The counter move for black. The shoulder hit is the ideal move to press down on white's formation. It prevents white from making his framework even bigger.


The usual way to respond to this kind of shoulderhit, is by trying to "push the opponent off your shoulder" by playing either 1 or 2. ]
(;W[dp]C[Wrong. ]
;B[qj]C[Whites three stones at the top are severely hurt.])
(;W[pi]C[Correct.]
;B[oj]
;W[oi]
;B[nj]
;W[rk]C[This is one way of playing lightly and defending the territory on the right side. ])
(;W[qj]C[Another good technique. ]
;B[pk]
;W[pi]
;B[nj]
;W[oi]
;B[ml]
;W[ql]C[Black succeeds in pushing white down.])))
(;B[ph]C[One of the other most frequently used techniques in this shape also involves a pressing strategy. ]
;W[qh]
;B[pf]C[Black finishes off his shape by playing this contact jump. 
This technique aims at pressing Whites base down and at the same time creating a wall for black that exerts power towards the left side. 

]
;AE[pf][ph][qh]AB[dc][id][ce][dj]C[In this position, black has a big framework on the top side. ]
;B[ph]C[Here the pressing move of black is extremely effective.]
;W[qh]
;B[pf]C[White is pressed down. Blacks two stones work together with the rest. 
This technique is useful for expanding your moyo!]
;W[pg]LB[qe:A]C[White usually plays here in order to prevent a black hane at A.]
;B[og]
;W[qg]LB[of:A][oh:B][ni:C][nj:D]C[Black has several options: He can play tenuki or strengthen his wall choosng from A to D.])
(;B[oj]LB[ph:B][pj:A]C[Combining the two ideas of Blacks reducing move at A and his moyo-technique with B, creates P10. 
This move is especially powerful in situations where both players have big frameworks facing eachother. ]
;AE[oj]AW[jp][qp][oq]AB[dc][id][ce][dj]LB[ph:A][pj:B]C[Here both the situations of the two earlier pressing moves of Black A and B have been combined. 
Both white and black have big moyo's on either side of the board.  ]
;B[oj]LB[ph:B][pk:A]C[In such a case this move can be extremely handy. 

White can react with A or B. 
A is the "obvious move". B is a fighting move. ]
(;W[pk]C[The standard answer. In this case good for Black. ]
;B[ph]
;W[qh]
;B[pf]LB[oj:1][pk:2]C[Great for Black. The exchange of black 1 for white 2 helps him a lot.])
(;W[ph]C[Fighting move. A mutual destruction of frameworks will follow.]
;B[qj]
;W[rj]
;B[qk]C[See bonus sgf file for a game between O Meien and Kato Masao where this sequence is played.]))
(;AB[qk][pp]LB[qg:1][rh:2][qk:A]C[What happens if whites "perfect base" is pressured from the other side and there already is a stone at A? 
Black can play 1 or 2. 


]
(;B[qg]C[The first major idea is this attachment. 

The following variations are taken from "Think like a pro - Haengma" by Youngsun Yoon 8p, published by Oromedia in 2006.

]
(;W[rg]C[Wrong. ]
;B[rf]LB[qe:1][qg:A][rh:2]C[Crosscut tesuji. Miai situation for black: black will be able to atari at either 1 or 2, splitting white into two. ]
(;W[pg]
;B[qe]
;W[qh]
;B[re]C[Great for black. His territory is huge.])
(;W[re]
;B[rh]
;W[qh]
;B[sg]
;W[pg]
;B[ri]C[Usually good for black. This ko is a huge burden for white and whites territory has been hollowed-out from the inside. ]
;W[rg]C[The ko is way more important for white than for black.]))
(;W[pg]C[Wrong. ]
;B[rf]
(;W[qe]
;B[qh]
;W[ph]
;B[ri]
;W[rh]
;B[rg]
;W[rj]
;B[sh]
;W[qj]
;B[pi]C[Blacks group on the side is already alive and black can cut. A difficult fight for white. ])
(;W[rg]C[Wrong. Goes back to one of the previous diagrams: Good for black. ]
;B[qe]
;W[qh]
;B[re]))
(;W[qh]C[Correct!

]
(;B[rf]C[Wrong.]
(;W[re]C[White can block!]
;B[pf]
;W[qe]LB[pg:A][rg:B]C[Miai: white can connect with either A or B.])
(;W[pg]C[Wrong, a mistake. This again goes back to one of the previous diagrams.]
;B[qe]
;W[rg]
;B[re]C[Good for black. ]))
(;B[qe]C[Correct. Best for both sides. ]
;W[re]
;B[pf]
;W[rf]LB[og:B][pg:A][oh:C]C[White is solid, but low. Black gains strength on the outside in sente. He can play A, B or C in sente. ])))
(;B[rh]C[There are many variations that start with this move, showing that there is still a lot of aji in whites formation.]
(;W[ri]C[The natural response.]
;B[qh]C[A sacrificing technique by black. ]
;W[ph]
;B[pi]C[Black will squeeze and gain something on the outside. ]
;W[qg]
;B[oh]C[Playing this atari first is crucial. ]
;W[pg]
(;B[qj]
(;W[rg]
;B[rj]
;W[sh]
;B[oj]C[Black gains strength on the outside. ])
(;W[oi]LB[mj:A]C[If the A side is very important, White can sacrifice his two stones on the side in order to gain something towards the centre.]
;B[pj]
;W[ni]
;B[rj]))
(;B[pj]LB[nj:A]C[If the A side is very important, black can also choose to play solid here immediately. ]))
(;W[qh]C[If black is strong all around and white wants to keep it simple. ]
;B[ri]
;W[rg]
;B[qj]
;W[oi]C[White secures his base, but black gains territory in sente. ])))
(;B[rc]C[Many of you know that this move is big in late middle game / endgame. But how big exactly?

This move is worth about 14 points. ]
;W[dp]
(;B[re]C[The normal follow-up. Big! 
This move is worth 12 points. ])
(;B[rf]LB[qk:A]C[A special follow-up. Can be even more severe. This move can sometimes be played when black has reinforcements around A. ])))
(;W[qh]C[There was one professional player who played here. We think he was scared! ;) You can view this interesting but strange move in the episode "bonus" tab. ]))