looking for old japanese couple who were close to us but lost contact

hello
im looking for this japanese couple who were a close friend of ours. they remained in contact till our phone line got cut off. they only called us thru land line phone. i will be going to japan soon, so i want to find them if i can.

Names:
Kazuo Sakurai- birthday is november
Sachiko Sakurai

they should be in their 70's -80's
should be around tokyo province