This is for Casa Matsubara 2.
The apartment is small (as stated). Will work for two people, for three, is just not comfortable.
The physical check-in process is easy once you figure out which door is yours (the building's ground floor is all Airbnb, once you know that, smooth sailing).
Unfortunately, the apartment wasn't clean as expected. The bathroom was clean, but the other areas were superficially cleaned - there was dust in plenty of places (bed included).
Maybe we've been unlucky as all the other reviewers stated this was spotless clean - nevertheless, this impacted our experience.
The third bed (floor bed) didn't have linens which the host provided the day after, once we told them. The host is very responsive to messages.
We asked for extra pillows (as the ones provided were very thin), but the host said they weren't available (albeit in the description it says so).
As stated by the host and other reviews, there's a train station attached to the house, so expect train noise 5am - 1am. Not too bad tho but avoid if you're a light sleeper.
The location is good enough, with a Lawson very close, the station right there, and 2 stops from Shimokitazawa (or 15 min walk).
Honestly, for the price we paid, this was the first time that we felt AirBnB didn't deliver either on the cozyness/experience of living like a local, and the convenience on price (there were great hotels for cheaper, but we like AirBnB!).