Bulky Five
Bulky five refers to a particular nakade shape of five points, i.e. an unsettled eye space, needing one more move to be sure of two eyes.
The vital point of the bulky five is the point. If White plays there, he is alive. If Black plays there, White is dead.
White can also live by playing at a (creating a bent four) or at b (creating a twisted four).
However, there are two points worth noting:
- the play at a and b may not work if the bulky five is crammed into the corner, as this will create a bent four in the corner or twisted four in the corner.
- both a and b leave Black with ko threats: playing at the marked point threatens to kill the whole group.
A play by White at the doesn't have these problems.
Linguistic note on Chinese
Chinese terms for the bulky five include 刀把五 (dāo bǎ wǔ), 刀板五 (dāo bǎn wǔ), 刀柄五 (dāo bìng wǔ), 刀五 (dāo wǔ). All of these terms refer to the fact that the eye shape looks like a knife. Specifically, the knife has a blade and a handle, and these are joined up at the point. Incidentally, the place where the blade and the handle joins () is also the vital point of the bulky five.
erislover: I think I have heard this called a "hatchet five" or something quite similar. To me, it looks like a butcher's meat cleaver.
unkx80: Actually, I think the bulky five is also known as "knife five".
Andrew Grant: I've removed the text 五目ナカデ (gomoku nakade) from the CJK box as "gomoku nakade" is not equivalent to "bulky five". Bulky five refers to one type of gomoku nakade only. There's also the cross-five shape.
See also