Can someone helps me on this position? I was sure that it is a winning position, but I messed it up,

[game;id:1667821;move:75]

I like C8. But others here are much more qualified to answer. :)

the simplest play usually does the job

http://www.trmph.com/hex/board#19,s14r13e6e7j8i10m9l11k11l9j10k10k8i12j11j13i13j12k12k13m12m13l13k15l14l15m14m15o14n16p15p16o16n18o8o17n17m18m17l18l17k18k17j18j17i18i16h17g16h16i14h15g15h14f14g13f13h11h13g14g12h12f10f11e11e12g11h9d12d13g10g8h8g9a11e9b11c10b9c11b12c12a14b13a13b14a15b15a16b17b16d16

Wow, Thank you very much Arek.

I have to admit, now I don't feel that I could win this game, because I'd never find the chain of moves you have played.

I just wonder, if this is the simplest way, what could be the sophisticated one :)

You could use your h17 stone to threat him on the bottom side like this: h17 threat

After few moves the situation would be like this: e9

This is a win for white player.

Thank you Maciej, it seems the position was not an easy position for a beginner like me :)