This apartment is as described - very cozy and in a great location! Very close to the massive Shinjuku train station, but far enough away to get a glimpse into a quieter neighborhood and a feel for a local's day-to-day life.
At least for most Americans, space is a bit on the cozier side (reminiscent of Manhattan apartments if you're familiar with those), though sufficiently roomy for a couple. Masami has placed a number of very helpful placards around to indicate what to do, what not to do, and how to do things.
First impressions were excellent - even from the entryway signs showed where to put our shoes and where we could have our shoes and where we shouldn't (at least to respect Japanese customs)!
Masami is very responsive to questions. She even preemptively let us know about an expected elevator outage for repair on our checkout date and volunteered to help us with our luggage! Even more impressively she showed up even though the repair service on the elevator hadn't yet begun (and we could still use the elevator).
Thank you again Masami and we look forward to staying with you again in the future!