RobertJasiek wrote:saxmaam wrote:a definition of “bad contact play”, which I didn't find.
You have searched for the wrong thing.
Dreadful mistake!
RobertJasiek wrote:The stated principle on p. 80 is:
"Do not use bad contact plays for attack."
Not actually tautologous.
RobertJasiek wrote:The following paragraph defines 'contact play', usually recommends non-contact plays for attack, specifies uses of contact plays and then explains in particular "[...] contact plays that are bad for attack if the attacker does not have strong nearby supporting stones".
Indeed unsupported contact plays are different in kind from supported contact plays, e.g. those occurring in the attach-extend and attach-block patterns. The latter can be used with intent to attack, the former tends not to be used that way. The tsukiatari or ramming play is typically for emergency defence.
The unsupported contact play is a typical non-emergency defensive play.
The underlying type of mistake being criticised here is "playing too close". That takes a bit of unpacking, but is one of the fundamentals.
The book's exposition also takes a bit of unpacking.
and 
are OK, while 
is over the top. But Black's result to 
is overconcentrated. The cut at C6 should come immediately, and White has problems here.
Black doesn't have good formations. Black does better on the lower side to 
. There follow some plays that don't mean much. Before living with 
, Black has the option of forcing with K5.
for 
is not a good exchange. The key point of shape here is Q5, which sets up further plays.
it is not so clear that the exchange made is better for Black. The endgame starts, however, and Black plays steadily from a solid position. Black 173 is a clear error (of the 123 type).
