(;GM[1]FF[4]AP[Drago:4.22.03]SZ[19]CA[UTF-8]AW[qs][rs][rr][sp][rp][qp][pp][op][np][nq]AB[oq][pq][pr][qr][nr][os][mq][mp][lo][no][oo][po][qo][ro]C[If White gets to play the
4-1 point black's shape
is short of liberties.]
(;B[ps]C[If Black plays there White can live.];W[sr];B[rq];W[qq];B[so];W[sq])
(;B[qq]C[This fails to kill too.];W[rq]
(;B[sr];W[ps])
(;B[ps];W[sr]))
(;B[rq]C[Black can try this first move.];W[qq]C[But it quickly fails.])
(;B[sr]C[This is the key point for two eyes.];W[qq];B[ps]
;W[sq]C[However White still lives.])
(;B[so]C[This calm move filling the outside liberty is the correct play.]
(;W[ps]
;B[rq]C[If White plays the 4-1 then this move catches White in bad shape.]
(;W[sq]
;B[sr]C[Snap-back shape.];W[qq];B[rq])
(;W[qq]C[Self-atari])
(;W[sr]
;B[qq]C[White is out of liberties.]))
(;W[qq]C[White still dies even if the eye space is enlarged with this.];B[sq];W[rq]
;B[sr]C[It is still self-atari for White to play 4-1.])))
