We truly enjoyed our stay at Koichi's apartment. Koichi is a great host. He responds very fast and is very kind. The price itself was good, I think. Especially, when you consider the great location of the apartment. Grocery stores and subway entrances are right at the corner.
The only thing which bothered us a little bit were the sometimes awful WiFi connection and the noisy air conditioning during the night.
All in all, we would absolutey recommend staying at Koichi's place and would definitely stay there again :)!