Bernd Kestler, a German knitter who lives in Yokohama asked people over the Internet and by other means in April 2012 to send crochet squares 20 cm in size.He eventually collected more than 11,000 pieces.
Together with people affected by the disasters as well as volunteers, Kestler stitched together the thousands of pieces in a gymnasium in Ishinomaki, Miyagi Prefecture, in September last year.
Around 11,000 of the pieces have been stitched together to complete the blanket in over two years and it broke the earlier record held by a piece in Kuwait, which measured 306 square metres, Kyodo news agency reported.
Upon receiving recognition by Guinness in January, Kestler said he could not have accomplished it without the help of people in the disaster area.