This 10-room inn is run by a friendly older couple. The tatami rooms are cosy and well-kept, though the building itself is old; if you’re staying two to a room, it’s worth ‘splurging’ for a room with a private bath (an extra ¥600). Larger rooms can sleep up to five.
It's a 500m walk from Gotanda Station, one stop past Meguro on the JR Yamanote line; note that it gets a bit of rail noise from the tracks nearby. From the west exit, head left, then right at the big road, followed by a left to walk along the river and under the tracks. In a few minutes you'll pass a large apartment complex; the inn is just behind it.
The air-conditioned rooms at Sansuiso Ryokan include a TV and yukata robe. Bathrooms and toilets are shared.
The Shibuya area is just a 7-minute train ride from nearby Gotanda Station. Shinjuku is a 13-minute train ride away. Tokyo Big Sight is about 20 minutes away by train, and Haneda Airport is a 35-minute ride.