We very much enjoyed our stay at Koichi's place. It was very clean, cozy, and located in a quiet residential neighborhood, 2 stops away from Shinjuku Station (via the Toei Oedo line.) It was near the station so the whole of Tokyo was very accessible. Bonus points that it had a Family Mart, 7 Eleven, Lawson, drugstore, casual Japanese restaurants, and McDonald's within easy walking distance. Highly recommended!