Nippori is known as fabric town and is dotted with fabric stores! If you are going for the first time, keep your eye open at the station because they have maps in English and Japanese. Tomato is the biggest store and there are 4 or 5 of them and there are loads of other stores too.
A couple of things if you go, don't try and tackle it with a pushchair/stroller. For starters it's next to impossible and some stores don't allow them inside. In fact, I would highly recommend leaving the kids at home if at all possible. I would also avoid the place like plague in March as it is the run up to the start of the new school year so it will be full of frantic mothers buying fabric to make the squillion of yochien bags.
No despite going to virtually every fabric store in the whole of Nippori, I didn't find any fabric I loved - insane right! I actually decided I would only buy fabric that I really needed, which is really hard for me!
This store is insane, it is floor to ceiling with bolts of fabric, there is no proper way to walk around, you literally have to scramble over the bolts! How they find anything in here is beyond me. I always worry about there being an earthquake when I'm in there, death by fabric isn't really what I want on my headstone!
I did pick up a bit of Echino fabric and some grey and blue dotty stuff but when I got home I decided I didn't like it for curtains! Fabric shopping fail!
But...the next day, I went to the mall and they have a Swedish designer Lagerhaus section and I found some fabric I loved there! I will share when I have the curtains done. They are half sewn in a pile at the moment.