A second guy joined him soon after. 

Now MtGox has announced they're moving offices. Here's their new release:

Dear MtGox Customers,

MtGox Co.,Ltd. (Japan) has moved to the address below:

MtGox Co.,Ltd.
Cerulean Tower 15F
26­1 Sakuragaoka­cho
150­8512 Shibuya Tokyo
Japan

Please address all documents/letters to the above address from now on.
Thank you for your kind corporation. 

Best Regards,

MtGox Team