This is an extract of a professional game. It is not that difficult. As it is a semai white will have to take away black liberties on the left, to avoid to write 120 different path I disabled all liberties except one at each move, it is perfectly equivalent so just look for the liberty on the left I allow you to play when you think of course that it is the good time to do so. Enjoy.
FOR STRONG PLAYERS: Theres is an unsolved question about black M2 instead of K1.
(;AW[cq]AW[dp]AW[dn]AW[fn]AW[fm]AW[go]AW[gp]AW[gq]AW[iq]AW[hq]AW[jn]AW[jo]AW[jp]AB[po]AB[fo]AB[fp]AB[fq]AB[ip]AB[hp]AB[ho]AB[gn]AB[hm]AB[jq]AB[kq]AB[kp]AB[ko]AB[dr]C[Find how Han Zenki 7p managed to get out this hell. Please do not play any forcing moves on the top black stones.]AP[goproblems]
(;W[fr];B[er]
(;W[gs];B[eq]
(;W[jr];B[hr]
(;W[ir]
(;B[kr]
(;W[ks]
(;B[js]
(;W[ls];B[lr]
(;W[ms];B[mr];W[ns];B[nr];W[os];B[or];W[ps];B[pr];W[qs]
(;B[qr];W[rs];B[rr]
(;W[is]
(;B[sr]C[CHOICE]
(;W[eo];B[ss]
(;W[cr];B[es]
(;W[ep];B[fs];W[gr];B[js];W[ks];B[ls];W[dq];B[js];W[ds]C[Congratulations! You have found the scrawling tesuji that win a liberty to avoid the ko. See source to get the real pro game.RIGHT])
(;W[dq]C[NOTTHIS]))
(;W[ep]C[NOTTHIS])
(;W[dq]C[NOTTHIS])
(;W[js];B[es]
(;W[dq]C[NOTTHIS])
(;W[ep]C[NOTTHIS])
(;W[cr];B[fs]C[Strange plan.])))
(;W[ep]C[NOTTHIS])
(;W[dq]C[NOTTHIS])
(;W[cr]C[NOTTHIS]))
(;B[fs]C[CHOICE];W[es];B[ds]
(;W[eo];B[sr]
(;W[cr];B[ss]
(;W[ep];B[js];W[ks];B[ls]
(;W[dq];B[fs];W[gr];B[js];W[es]C[Yeah! if black plays this way there is an interresting double ko pattern that white wins unconditionnaly.RIGHT])
(;W[fs];B[hs];W[gr];B[hr];W[dq]C[RIGHT]))
(;W[dq]C[NOTTHIS]))
(;W[dq]C[NOTTHIS])
(;W[ep]C[NOTTHIS]))
(;W[ep]C[NOTTHIS])
(;W[dq]C[NOTTHIS])
(;W[cr]C[NOTTHIS])))
(;W[ss];B[sr]C[Oops.])
(;W[ep]C[NOTTHIS])
(;W[dq]C[NOTTHIS])
(;W[cr]C[NOTTHIS])
(;W[eo];B[ss]C[Black is faster.]))
(;B[rs]C[If black has a very large number of ko threats he can play this way, but risks about 20 points more.];W[qr];B[qq];W[rr];B[sr]C[];W[ss];B[nk]LB[nl:A]C[Play at A to answer the first threat.];W[nl];B[rs];W[rq];B[rp];W[ss];B[ok]LB[ol:A]C[Play at A to answer the threat.];W[ol];B[rs];W[is];B[sq];W[ss];B[pk]LB[pl:A]C[Play at A to answer the threat.];W[pl];B[rs]
(;W[ep]C[NOTTHIS])
(;W[dq]C[NOTTHIS])
(;W[cr]C[NOTTHIS])
(;W[eo];B[js];W[ks];B[es]
(;W[dq]C[NOTTHIS])
(;W[ep]C[NOTTHIS])
(;W[cr];B[fs];W[gr];B[ls];W[ep];B[js]C[Ko again. Black can play this variation if he has a very large number of ko threats, but risks about 20 points more on the right.RIGHT]))))
(;W[ep]C[NOTTHIS])
(;W[dq]C[NOTTHIS])
(;W[cr]C[NOTTHIS])
(;W[eo];B[ms]C[Black is faster.])
(;W[is];B[ms]
(;W[ep]C[NOTTHIS])
(;W[dq]C[NOTTHIS])
(;W[cr]C[NOTTHIS])
(;W[eo];B[js];W[ks];B[ls]
(;W[cr];B[es];W[ep];B[fs];W[gr];B[js]C[Only a painful 45 points ko.])
(;W[dq]C[NOTTHIS])
(;W[ep]C[NOTTHIS]))))
(;W[ep]C[NOTTHIS])
(;W[dq]C[NOTTHIS])
(;W[cr]C[NOTTHIS])
(;W[eo];B[ls];W[is];B[ks]
(;W[dq]C[NOTTHIS])
(;W[ep]C[NOTTHIS])
(;W[cr];B[es]
(;W[dq]C[NOTTHIS])
(;W[ep];B[fs]C[Black is faster.]))))
(;B[lr]C[If someone knows why the professional did not play there, I would be glad to see it. (do not forget black F1 tesuji).];W[hs];B[js];W[cr];B[fs];W[gr]
(;B[ds]C[RIGHT])))
(;W[js];B[hs]
(;W[ks];B[lr]C[Pushing like this cannot give you extra liberty, black will only play on the second line. So stop it now please.]
(;W[eo];B[es]
(;W[cr];B[fs];W[gr];B[ls])
(;W[dq]C[NOTTHIS])
(;W[ep]C[NOTTHIS]))
(;W[ls]C[NOTTHIS])
(;W[ep]C[NOTTHIS])
(;W[dq]C[NOTTHIS])
(;W[cr]C[NOTTHIS]))
(;W[ep]C[NOTTHIS])
(;W[dq]C[NOTTHIS])
(;W[cr]C[NOTTHIS])
(;W[eo];B[ks]
(;W[cr];B[es]
(;W[ep];B[fs]C[Black is faster.])
(;W[dq]C[NOTTHIS]))
(;W[ep]C[NOTTHIS])
(;W[dq]C[NOTTHIS])))
(;W[hs];B[js]
(;W[eo];B[es]
(;W[cr];B[fs]
(;W[ep];B[ks];W[dq];B[gr];W[fr];B[gr]C[Black is faster.])
(;W[gr];B[ks])
(;W[dq]C[NOTTHIS]))
(;W[ep]C[NOTTHIS])
(;W[dq]C[NOTTHIS]))
(;W[ep]C[NOTTHIS])
(;W[dq]C[NOTTHIS])
(;W[cr]C[NOTTHIS]))
(;W[ep]C[NOTTHIS])
(;W[dq]C[NOTTHIS])
(;W[cr]C[NOTTHIS])
(;W[eo];B[js]C[Black is faster.]))
(;B[lr];W[cr];B[es];W[eo]
(;B[fs];W[gr];B[kr];W[ep];B[js];W[dq]C[White is faster.RIGHT])))
(;W[gr];B[kr];W[ir];B[js])
(;W[is];B[gr]))
(;W[hr];B[jr]
(;W[ep]C[NOTTHIS])
(;W[dq]C[NOTTHIS])
(;W[cr]C[NOTTHIS])
(;W[eo];B[is];W[hs];B[es]C[Black is faster.]))
(;W[ep]C[NOTTHIS])
(;W[dq]C[NOTTHIS])
(;W[cr]C[NOTTHIS])
(;W[eo];B[ir]C[Black is faster.]))
(;W[gr];B[eq]
(;W[jr];B[kr]
(;W[hs];B[ir];W[js];B[fs];W[ks];B[ls];W[is];B[lr]
(;W[ep]C[NOTTHIS])
(;W[dq]C[NOTTHIS])
(;W[cr]C[NOTTHIS])
(;W[eo];B[es]))
(;W[ir];B[hs]
(;W[ep]C[NOTTHIS])
(;W[dq]C[NOTTHIS])
(;W[cr]C[NOTTHIS])
(;W[eo];B[fs]))
(;W[is];B[ks]
(;W[hr];B[js])
(;W[hs];B[js];W[ir];B[fs])
(;W[ep]C[NOTTHIS])
(;W[dq]C[NOTTHIS])
(;W[cr]C[NOTTHIS])
(;W[eo];B[js];W[ir];B[fs]))
(;W[js];B[ks]
(;W[hs];B[ir];W[is];B[fs])
(;W[ir];B[hs]
(;W[ep]C[NOTTHIS])
(;W[dq]C[NOTTHIS])
(;W[cr]C[NOTTHIS])
(;W[eo];B[fs]))))
(;W[ep]C[NOTTHIS])
(;W[dq]C[NOTTHIS])
(;W[cr]C[NOTTHIS])
(;W[eo];B[ir]LB[fs:1]LB[gs:2]LB[hr:3]LB[ep:1]LB[dq:2]LB[cr:3]LB[ds:4]LB[es:5])
(;W[ir];B[hs]C[Black is faster.]))
(;W[fs];B[ir])
(;W[jr];B[gr]C[You are in big trouble.]))
(;W[jr];B[fr]C[You are in big trouble.])
(;W[hn]C[NOTTHIS])
(;W[hl]C[NOTTHIS])
(;W[eq];B[gr])
(;W[hr];B[fr]C[:(])
(;W[hs];B[fr]C[:(])
(;W[im];B[hl]C[There is nothing there and it is a very bad move on the outside.])
(;W[il];B[hl]C[There is nothing there and it is a bad move on the outside.]))