|36.k20 was necessary and not at all difficult to find.

|33.r17 34.s6 35.t7 36.q5 37.u5 38.r7 39.s9 40.q9 41.t11 42.u13

Here are some highlights of the game in my opinion:

|14.j18! because if I attack to the right the following happens: 15.l17 16.l14 17.j16 18.j9 19.g11 20.i4 21.l5 22.i6 and black can play (23.b2 ignore) 24.n6 or 24.k12.

So I decided to play a global Medcalth with |15.f18! and improve the connection like seen in the game. I need |17.g11 to come to the top, I thought the north will be played out the following way: 18.i4 19.l5 20.k5 21.j6 22.m4 23.r6 24.s4 25.o3 26.n6 27.t7 28.q5 29.w4 30.r7 31.r8 32.q9 33.q10.

|19.n16? |21.p17? moves that will do the job, but maybe not the best... I was wrong, like the excellent move |30.r11!! proved, with which the game already would be over if black plays after |31.t16? 32.s4! 33.t7 34.n6 35.w4 36.q9 or 33.s3 34.q5 35.t5 36.r7. Just for completion, the other side is won with: |31.s8 32.q17 33.s16 34.r15.

If I would play |19.l19! already then, I would probably win the game: 20.k20 (more or less forced as seen in real game) 21.m17...

My moves after 18th just were not really bad, but not good enough for that level. Another mistake of me was completely ignoring that David can play |34.r20 or |34.r16, I was somehow only looking at |34.q17? which would allow me to win with 35.u14, then black needs to connect in the middle because of u9, so 36.t12 and white can break through with 37.r16.