Same here, actually, only it wasn't Yamamoto who sealed the deal for me, but the story's weird, almost experimental flirtation with seriousness. It confirmed that in spite of the talking babies and magic bullets and people running around everywhere with no pants on, Amano could actually write characters and stories with some sort of depth behind them. I was very pleased to discover this.

Going on three hundred chapters later, and we've still got that weird combination of crack and serious going on, come to think. It's one of the things I really love about KHR.