This funding opportunity has now passed. The next deadline is likely to be December 2016

Funder deadline 9-Dec-2015
Research Services deadline 2-Dec-2015 (-5)
Law Faculty deadline for first draft for review 18-Nov-2015 (-15)
Law Faculty deadline for initial expression of interest 11-Nov-2015 (-20)

From the website:

"The Japan Society for the Promotion of Science (JSPS) Postdoctoral Fellowship Programme for Overseas Researchers is for early career researchers who wish to conduct research in Japan. This scheme provides funding for early career postdoctoral researchers to conduct cooperative research in Japan, with leading research groups in Japanese universities and other institutions, under the guidance of a host. The British Academy is an overseas nominating authority for this scheme, which is funded entirely by the JSPS. In this capacity, the British Academy nominates a designated number of candidates each year."

These fellowships are for researchers within 6 years of a PhD and applicants need to arrange in advance a research plan with a Japanese host researcher employed at a Japanese university/research institution. Full funding is provided for 12 - 24 months.

Read the full scheme details on the JSPS Postdoctoral Fellowship website.