The Lucky Gods of Otsu — I.J. Parker

If ever Akitada needed luck, it is now! Things are not going well for him. His new boss is out to get him, his daughter is in love with the wrong man, his ex-wife's affairs come again to haunt him, and he fears he is too old and too poor to deal with any of it. Then his old friend dies suddenly from a case of indigestion that looks suspiciously like murder and the problems escalate into the deadly violence of two ruthless killers. He has to save not only his career and his reputation, but his life.