I need to buy math books from Japan for GRADE 1 (age 6) to GRADE 6
(12) in ENGLISH.

Though the books would be in English, the books must
- have been written according to Japanese curriculum AND 
- be for Japanese (English medium) schools (possibly targeted at
children from expatriate, mixed, or anglophile families).

While most elementary math books must be in Japanese, there will be
few sets of books in English as well.

Japan has one national math curriculum but not one set of books.
Several publishers publish books based on the national curriculum. The
local educational authorities, not the schools, decide which books
will be used in schools in their area. So, one area will have one set
of books.

REQUEST:
Please provide title of the books, name of the publisher (and if
possible the website address through which I can order the books) for
at least one set (or 2-3, if possible) of books.