The first multilateral attempt explicitly to control the export of supercomputers for non-proliferation purposes was the U.S.-Japan Supercomputer Agreement of 1984. Modifications of the agreement were adopted in 1986, 1990, and 1994. At that time, the two major supercomputer manufacturing nations agreed to coordinate the sale of these machines to third parties. The agreement supplemented CoCom by controlling transfers to non-Communist countries.
In 1993, the United States liberalized its export controls on supercomputers (500 MTOPs for CoCom; 2,000 for the bilateral agreement). The Japanese protested the unilateral nature of this decision and only raised controls to 1,500 MTOPs. The controls prohibited sales to end-users known to be engaged in weapons development, proscribed activities, or known to be terrorist entities.