There is a large, beautiful courtyard and garden that behind the property with Sakura trees, manicured garden landscaping and a koi fish pond. This courtyard actually connects to two other Prince hotels (non-Marriott), but in the same Hotel ownership group. They're all equally nice from what I saw in the lobbies. Look at views in Google Maps and you'll see it's like a complex with three hotels adjacent to the train station and some small residential neighborhood.

I enjoyed being in that area since it was so close to Shinagawa station. The rooms are also quite large for Japanese standards.