TOKYO, Sept 26 (Reuters) - The family office linked to Nintendo's founder plans to raise its buyout bid for Japan's Toyo Construction, a source told Reuters, after it successfully reshuffled the board that had resisted its offer.

Yamauchi-No.10 Family Office (YFO), the largest investor with some 28% in Toyo, is now planning to offer 1,255 yen ($8.44) per share, up from its initial offer last year of 1,000 yen, the source with direct knowledge of the matter said.

The source declined to be identified as the matter is not public.

YFO's initial 1,000 yen offer was higher than a 770 yen per share offer from an industry rival which Toyo had endorsed at the time, when its shares were trading at around 600 yen.

It took about nine months for Toyo to form a special committee to assess YFO's offer, which YFO said acted against shareholders' interest.

At an annual meeting in June, Toyo shareholders approved seven of nine directors backed by YFO, allowing these directors to form a majority of the board. ($1 = 148.7100 yen) (Reporting by Makiko Yamazaki; Editing by Alexander Smith)