I picked up this magazine, Newton, Graphic Science Magazine, at the local book shop, to have a look through. It has great pics and easy to follow instructions for fun experiments-even with limited Japanese.
There is also a web site, http://www.newtonpress.co.jp
You can become a member for 12,000 yen per year.
They have lots of notices to science events happening around the country … a Science Camp for kids was advertised open to non-members as well.