Since nobody came forward to present the solution, I'll present what I think it is. --unkx80
Up to Black 7, because of shortage of liberties, White is unable to play at a.
Note that Black 3 threatens the cut at a.
I first thought that this would work, but... -Kuolema
tderz: Looks close to GATEWAY TO ALL MARVELS #5 problem, but is much easier here.
Referenced byOD1PAug6Problem