Re: [gnugo-devel] hoshi patch

[bump]

> This patch adds more variations after the low approach, low pincer, one
> point jump.  This is probably not ready for CVS, but I'd like to solicit
> comments.  What more does this patch need?  What variations do we want
> gnugo to play?  Clearly, making the second jump is bad; do we want it to
> play the shoulder hit, or not jump in the first place (ie invade or make a
> double approach instead)?

First some general comments about this position. I'll refer to the
file hoshi_keima.sgf for move locations.

The original one space jump at P14 might be inferior to
a second kakari at O17 or O16. I posted one variation in
this joseki in a previous message, and I see this is in
the file so I guess Evan added it.

One move in this hoshi_keima.sgf I'm not sure is joseki:
I wouldn't play R17 in the following line because it seems
to me that this leads to the following position which looks
slightly better for B.

(;GM[1]FF[3]
RU[Japanese]SZ[19]HA[0]KM[5.5]
GN[Hoshi joseki variations]
DT[1999-05-10]
SY[Cgoban 1.9.5]TM[-];B[pd]C[0];W[qf];C[#kogeima kakari];B[qh]C[j
]
MA[mj];C[#hasami];W[nc]MA[ki];B[pf]MA[li];W[pg]MA[li];B[qg]MA[li];
W[qc]MA[li];B[pc];W[pe];B[of];W[oe];B[qe];W[qd];B[rf];W[re];B[qf];
W[pb];B[ne];W[od]
)

Here's the variation that I think is joseki, and a
refutation of a mistake by B.

(;GM[1]FF[3]
RU[Japanese]SZ[19]HA[0]KM[5.5]
GN[Hoshi joseki variations]
DT[1999-05-10]
SY[Cgoban 1.9.5]TM[-];B[pd]C[0];W[qf];C[#kogeima
kakari];B[qh]C[j
]
MA[mj];C[#hasami];W[nc]MA[ki];B[pf]MA[li];W[pg]MA[li];B[qg]MA[li];
W[pc]
(;B[qe];W[qc]C[Joseki
])
(;B[qc];W[pe];B[of];W[qd];B[od];W[oe];B[ne];W[qe];B[nd];W[nf];B[og];
W[rc]C[W has the advantage.
])
)

This double kakari might be a good joseki to develop. There
will be a few more variations but a lot less than the
shoulder hit after the one space jump.

The second one space jump is also not very good but it is 
also not so bad that we have to rush to revise this line of play.
It has the advantage of simplicity. 

If we want to replace this with the shoulder hit, there are
going to be many, many variations. Arend suggested that
we not play it as W. Perhaps this is best.

If we do develop the shoulder hit, the joseki will have to
be very tested. W needs to know enough to invade the 3-3
point early if the original kakari stone gets cut off, etc.
I think some patterns would be best hand coded with x, o and
? in order to deal with transpositions in the order of play.

Dan