4-4 point low approach low extension, slide, attach
Apparently, is a fairly recent Korean development from a dozen years ago.[1] It aims to develop a group on either side of the white kakari (develop on both sides).
White must play hane on top. Next at a or b is normal.
Cho U played this way against Lee ChangHo on 2005-02-23 during Nongshim Cup,6,Korea,Nongshim -Jared
If White plays hane underneath... she will be pressed low.
[1]
Bill: Actually, it has been around for a while. It appears, with variations, in Suzuki and Kitani's Small Joseki Dictionary, published in 1965.
John F. It goes back to 1934 in Japan in the GoGoD database. But then it did not reappear in games we have, except in some instances with more stones round about, until 1991 when it re-emerged in Korea. Mark Hall collected a lot of these games and dubbed the opening the Korean Joseki. We have over 200 examples, and it's still being played widely.