(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]RU[Japanese]SZ[19]KM[6.50]TM[1800]OT[5x30 byo-yomi]DT[2013-02-16]PC[The KGS Go Server at http://www.gokgs.com/];AW[da][fa][bb][db][eb][bc][cc][ad]AB[ba][fb][gb][dc][ec][cd][ae][be][de]C[black to play. What's white status ?];B[ca];W[aa](;B[ab];W[ac](;B[aa];W[cb];B[ba];W[aa];B[ab];W[ca]C[white is alive because of one liberty])(;B[bd]C[this is Ko]))(;B[bd]C[Ko];W[ac];B[ab])(;B[ac](;W[ab];B[bd]C[white is dead])(;W[bd];B[ab];W[aa];B[ab];W[cb]C[white is also dead, black does not have to answer])))