In the late occupation, the United States began some subsidization through its aid programs, the Korean War affected shipping recovery, and occupation authorities helped Japanese firms re-enter overseas lines and conferences. The event that triggered a transformation in NYK strategy, leading to the fourth period, was known as the "Mitsui Fight." This was an unsuccessful three-year attempt in the mid-1950s by NYK and OSK, in cooperation with European firms, to keep Mitsui Senpaku KK—Mitsui Bussan's former division—out of the Far Eastern Freight Conference. All firms suffered in this struggle, but Mitsui survived because of its strength in the tanker business which had supported it during the competition. This realization led NYK to undertake its strategy of diversification, a move accompanied by a restructuring of its business division into three major services—liners, trampers, and tankers.