Diamond
Table of contents | Table of diagrams Diamond shape Diamond alive in the corner Diamond dead in the corner Diamond in the corner corner Diamond shape Ponnuki |
Diamond Shape
This shape is called a diamond or diamond shape.
iopq: A diamond survives in the corner. It's sometimes useful for invasions or ko threats to know this. Don't let one complete in the corner! Circled points are ko threats for white.
This shape is dead, though.
This is life based on who gets to move. White can play the marked stone as a ko threat.
White can move in the marked point to kill Black, just knowing about the diamond in the corner! If the diamon does not complete, Black dies.
Bill: I believe that this is the diamond shape. (See T. Wolf, The diamond. British Go J. 108 (1997) 34-36.)
aLegendWai: Hehe... An interesting diamond. I would like to call it compressed diamond. However it is no longer a good shape than the normal one.
A compressed diamond cannot be in good quality. ^^
Ponnuki
In contrast, a ponnuki is the process of capturing a single stone leaving such a shape, not the shape itself. [1]
Difference between Ponnuki and Diamond
Charles Matthews: Ponnuki implies local tally BBB (four black stones played, one white captured, 4 - 1 = 3). If you make a diamond as Black without capturing a white stone that is local tally BBBB. The former is proverbially worth 30 points, i.e. ten points when you divide by the tally; the latter would therefore give only 7.5 points per play.