In fact in this neighborhood there are the headquarters of the Sunrise Animation, the studio that created the popular first series in 1978 (Gundam 0079) and that in the following years will release several other TV series, OVAs and whatnot, making this series one of the most popular of all times in Japan.
The nearest station to get to this neighborhood is precisely Kami-igusa station, along the Seibu Shinjuku line
(Pay attention: not all trains of this line but only local trains, 各停, stop at this station).
To take this line from Shinjuku, you have to head to the Seibu Shinjuku station, which is located just north of the main Shinjuku station, exactly under the Prince Hotel (a red building) near Kabuki-cho.
Just outside the south exit of Kami-igusa station you will immediately see a statue of Gundam:
To reach the headquarters of the Sunrise start to walk towards left (east), along the way you could see things like that:
Barely 100 meters far from the south exit of the station there is this small building, the headquarters of the Sunrise Animation. If you expected some kind of impressive high-rise building, perhaps you'll be a little disappointed, but it seems that you need just a few rooms to create an anime famous all over the world!
On the ground floor of the building there is an automatic sliding door, unguarded but monitored by cameras, where you can freely enter.
Inside there is a room with some giant model and a hundred models from the various Gundam series into a showcase.
This room is all is possible to visit, you can't go beyond the door on the left because it is accessible only by authorized personnel.
dentro la "stanza" visitabile presso la sede della Sunrise Animation a Kami-igusa
Here below a video of the whole itinerary on foot from Kami-igusa station up into the Sunrise building. I speak italian in the video but I don't say anything important.