Japan’s government moved to address mounting concerns about a weakening yen by pledging assistance for small companies hurt by cost increases spurred by the falling exchange rate. The trade ministry today unveiled an initiative pressing large businesses to assist small firms to pass on rising input costs, aiding policy makers’ broader plan to kindle sustained inflation in an economy marred by two decades of stagnation. Prime Minister Shinzo Abe told lawmakers in Tokyo that big firms and exporters should pass on the benefits they have reaped from the weaker yen to smaller enterprises. This week’s slide in the yen to its lowest against the dollar since 2008 has fanned concern in the world’s third-largest economy.