Catenaccio joseki
This is the so-called catenaccio joseki, referring to the defensive football style of the Italian national team in the 80s [1].
This joseki used to be more popular than it is now. In itself it is considered too low by a.o. Alexandre Dinerchtein but these lines have survived as niche joseki, for some special contexts.
Alternative for
(colors are reversed) There is also the possibility of Black playing the peep , seen in catenaccio joseki follow-up here earlier, as soon as White slides into the corner.
Later when White's corner is surrounded Black has a trick, see /Variant Life And Death
Alternatives for
Kitani Minoru invented (or borrowed) [2] a joseki in which he played at the 3-3 point. It appeared in Kitani-Shimamura, 1956 2nd Top Position Tournament league. After
, White plays at the circled point.
The effect of White's three stones that include is to create bad aji for Black's stones on both sides. Black cannot attach immediately at a and there are other dangers if black tries too hard to capture White's stones.
It had some popularity in the 1970s; much less fashionable now. A likely reason why this "joseki" is rarely played out is because the one-space jump followed by the 3-3 invasion is not really following the flow in most cases - the feeling is that White wants to make moves both outside and inside the corner, which appears somewhat greedy. (Compared to the usual joseki where White directly enters the 3-3, White sacrifices the outside for a fairly large corner.) This results in a smaller corner, while the outside stones are somewhat heavy and subject to attack.
is supposed quite generally to be bad shape, once
is played.
Indeed, Yang Yilun teaches that either should be at a or
should be at b. a and b together are also bad shape.
There was an old Go World article about this by Kato Masao.
[1] It is not widely accepted as a name and seems to be introduced to SL by Stefan. Catenaccio, for those who do not speak Italian, means lock
[2]