Guzumi at Top Right (2007 - 2009)
The Hasami-Tsuke in the Upper Right
(Referenced by 38) The hasami-tsuke of - a suggestion of Harry Fearnley - is possible now, after the "guzumi exchange" of the -/-stones, and the first exchange of / in the top right corner. Black's single stone at weakens White's corner. |
|
After the sequence shown, it will become evident that the false eye at is an additional approach-move liberty. White cannot approach directly at , but must play first, because there is another (potential) approach-move liberty at . , and , form an effective liberty for Black. So, despite having lost a direct liberty, Black's liberties remain stable. |
|
For comparison, here is the sequence of the Fujisawa Solution ( 754). Later on, White will occupy Black's liberties in the corner (, ). White has four points of territory more () than with the hasami-tsuke. |
|
Should White later capture Black's top right group (), it has increased by two stones due to the hasami-tsuke (), but White has played two additional stones (, ) in her corner, too. Thus the final score remains unaffected. |
|
However, the hasami-tsuke is not possible without the guzumi, as well. The diagram shows the upper right corner after the reduction by Black in the professional solution. The Black group has thirteen liberties (). It is shown earlier ( 742) that Black must not put any of these at risk. |
|
Here, Black reduces with the hasami-tsuke . |
|
Tenuki: ; |
But, if Black later connects his stones, he will end up with only ten liberties (). However, we have to include his tenuki with , and , taking liberties of White's group on the left side. So, Black has effectively lost one liberty. Therefore, Black can not connect both of his pivotal stones and (), making the hasami-tsuke worthless. |
Tenuki: ; |
Black should play tenuki with to save his big group (with ten liberties, and three tenuki moves), and White keeps four points of territory ( / ). Black gained nothing by the hasami-tsuke here. |