Without image of the tea pot hard to say which time period but these marks were extensively used during the Meiji Period (1868-1912) however some traditional manufacturers still use those marks today.
To my knowledge no links available to learn more about Chinese and Japanese silver hallmarks. You could buy World Hallmarks Volume II Asia, Middle East, Africa.
Extra information see:
viewtopic.php?t=24259&start=20#p59564Peter.