This problem is from Guanzi Pu – possibly my favourite of the classic problem collections thanks to its varied and relatively difficult problems.
While a (most likely illegal) pdf version of the book been posted around on Western go websites, its solutions often seem to be wrong. I would instead recommend interested players to invest in a six-volume physical copy, which can for example be bought from Hebsacker Verlag.
Black to play.
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Solution added.
I might have a gross blind spot, but Black J19 seems to threat either a connection or a throw-in.
Cheers,
Vesa