posetcay: D4 (and F3-F2-D4) as first move should be the only correct answer here, all other variations give white an extra point since opponent needs to answer D4 at E2. The problem with previous solution was that opponent answered E2 at F2, but opponent can just play D3 as response to E2 and it becomes point losing exchange. I have updated the solution tree.
todbeibrot: white can start with f3. he can also play this move later. after d3 white should play f3f2g2e1g3 and the result is a ko. there is no difference to e2d3f3f2...
Thanks!