We are in the Kashiwa campus of the University of Tokyo, which is about 25 km north of Tokyo:
To get here, take a Tsukuba express train to Kashiwanoha-campus station, then take a bus to Todai-mae bus stop. (Or you can take a nice 30 minute walk through the park.) More info.
We often meet in the Satellite Building in front of the station:
If you need to write a phone number for us in some document, you could perhaps use:
+81-4-7136-4003 (UTokyo GSFS)