(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.00]
PW[White]PB[Black]
AW[ra][bb][db][nb][qb][dc][nc][oc][pc][bd][cd][dd][nd][pd][ae][be][ne][oe][rn][ao][bo][ro][cp][qp][qq][sq][br][cr][pr][qr]
AB[an][da][cb][eb][mb][rb][sb][ec][mc][qc][rc][ed][md][ce][de][ee][me][pe][qe][af][bf][nf][of][pg][cm][qm][rm][sm][bn][dn][qn][eo][qo][dp][pp][dq][nq][pq][dr][fr][or][ps]
LB[dg:D][lg:A][nn:B][gp:C]
C[Four more problems that often come up in games and are not too difficult.(once you know the answer!) 

Hint A - how to play without making a ko - first find the eye stealing shape point.

Hint B - This corner shape or very similar comes up often in actulal play,  find the forcing move and it should be easy to see the value of the hane

Hint C - First principals will succeed here. 

Hint D - an often used sacrifice technique - but easy to miss the blind spot. ]
;W[ij]
;B[oa]
;W[na]
;B[pb]
;W[jj]
;B[rp]
(;W[so]
;B[rr]
(;W[rq]
;B[qs]
;W[ik]
;B[cs]
;W[bs]
;B[bq]
;W[cq]
;B[ar]
(;W[ap]
;B[co]
;W[jk]
;B[cc]
(;W[ba]
;B[bc])
(;W[bc]
;B[ba]
;W[ca]
;B[cb]))
(;W[aq]
;B[ap]
;W[bp]
;B[aq]
;W[as]
;B[aq]))
(;W[rs]
;B[rq]))
(;W[sp]
;B[so]
;W[sn]
;B[so]))
