Since visiting for the first time in 2011, I have been fascinated with the level of lean excellence at Rinnai. I recently had the pleasure to interview Mr Masao Kosugi, Director of Rinnai Corporation. Kosugi has been at Rinnai since they first started studying the Toyota Production System (TPS). Being a leading Japanese corporation, I am sure Rinnai were practicing a quite reasonable level of lean back in 1979. But a visit from Toyota’s Taiichi Ohno changed everything.