Black to help the marked stones. KataGo came up with a rather surprising move here: instead of defending directly, look for a way to exploit white's thin connection and build up strength.
(;SZ[19]AP[Jago:Version 5.0]GM[1]FF[1]CA[UTF-8]AB[pd][pq][cd][np][pl][on][qr][or][fc][dc][ed][bd][ck][bc][ch]AW[dp][po][qf][lq][qj][qq][qp][rl][dd][ce][de][be][cc][cm][eh]TR[ck][ch][eh][de]GN[2024-01-21-Fox-someone-eccles30](;B[ff];W[ef](;B[ee];W[dh](;B[eg];W[cg](;B[ci]C[RIGHT
Black has made a base on the left and has some nice potential at the top as well.])(;B[dg];W[ci];B[bh];W[bi];B[bg]C[RIGHT
This is a good trade for black]))(;B[ci]C[RIGHT
Black has made a base on the left and has some nice potential at the top as well.]))(;B[fg];W[eg])(;B[eg];W[dg];B[fg];W[dh]))(;B[ek];W[ee]C[White builds strength at the top, and the fight will be more difficult for black later.])(;B[dg];W[ee];B[eg];W[gf]C[White builds strength at the top, and the fight will be more difficult for black later.])(;B[ee];W[dg]C[Right general direction, but you can do even better.])(;B[eg];W[dg];B[dh];W[fg];B[ef];W[ee];B[ff];W[fe]C[Oops, you let white play a driving tesuji])(;B[ei];W[fi];B[ej];W[dh];B[ci];W[ee]C[Not bad, but black could have gained more at the top.])(;B[ef];W[ee];B[fe];W[cb];B[bb];W[ff];B[df];W[ge];B[fd];W[lo]C[Black can capture some stones, but white has a lot of aji in the corner plus potential to build on a large scale. It's hard to believe white can just give away the corner like this, but KataGo insists that black is 2 points worse off this way compared to the recommended line!]))