Jang was friendly and helpful, he was kind enough to help me call to make a lunch reservation as we cannot speak Japanese. The location was very close to a Lawson and the train station, but there was two long flights of stairs that you have to carry your heavy luggages up when getting to the apartment. To get to most places, you would most likely have to change trains at Shinjuku. The home was too small for 4, we had difficulties finding space to open our luggages, but this is more or less expected of city apartments.
Our only gripe was the beds. Jang provided 4 beds for us, which sounds plenty but the sofa bed was very uncomfortable. Nobody slept on it. The main double bed was small and the mattress was sunken in the middle, which made it uncomfortable for two to squeeze. Futon on the floor was ok but a little bit too thin/hard for a side-sleeper.
Overall, Jang's place was relatively clean, but definitely more of a Korean home than a Japanese home.