This was a really amazing experience! Naoki was responsive via the Airbnb app (make sure you install the app!) and provided really detailed instructions on how to get to the apartment. The area of Takadanobaba is a vibrant youthful area (Waseda Uni is nearby) and there is basically everything you need there. The bunk bed was soft and comfortable and in end-winter (early March 2018) the heater worked perfectly well. I believe Tokyo apartments tend to be tiny and this space was good for me (solo female traveller, first time in Japan), can probably fit a partner in, but make sure its a your other half/a really really good friend because it can be slightly awkward when you poop and there is no bathroom door.