We stayed at Koichi's place in Shinjuku. Koichi is super nice and an excellent host. Great amenity, quick responses to all questions, provide great local tips (just ask). He even went out of his way to pick us up and drop us off at the train station.
The location is right in the heart of Shinjuku (10 minutes walking distance to major shopping center, train stations). The place is a bit old and small, but comfortable per Tokyo's standard (and for the price paid). We were highly satisfy overall !!