From an article on Flight Global:-
Kongsberg has entered into a deal with Tokyo to supply its Joint Strike Missile (JSM) for use by the Japan Air Self-Defense Force (JASDF).
The Norwegian company disclosed the deal in a statement, but said that neither it nor the Japanese government are disclosing the number of weapons or the value of the contract. The timing of deliveries was also not discussed.
“The international [Lockheed Martin] F-35 user consortium is showing great interest in the JSM and Kongsberg is very proud to have been selected by Japan to provide the JSM for their F-35 fleet,” says Eirik Lie, President, Kongsberg Defence & Aerospace.
“This is a major milestone for the JSM program, entering into the production phase.”
The F-35 can carry two JSMs internally. At the Japan Aerospace show in 2016, the company told FlightGlobal that the weapon can also be adapted to serve aboard the Kawasaki P-1 maritime patrol/anti-submarine warfare aircraft.