This is a good deal for Japan, they get to sell the Patriot missiles to the U.S. and maintain their charade of not providing aid to Ukraine:
Japan will begin selling domestically produced missiles to the United States in a bid to bolster U.S. weapon supplies in the region. The U.S. will purchase approximately $19.6 million worth of Patriot Advanced Capability-3 interceptors, or PAC-3 missiles, the Japanese Defense Ministry’s agency for acquisition, technology and logistics said in a Sunday news release. The number of missiles included in the deal was not disclosed. (….)
“By providing Japanese-made PAC-3 missiles to the United States, Japan can indirectly assist Ukraine with much-needed air-defense systems, but without provoking a public backlash,” Brown told Stars and Stripes by email Wednesday.
You can read more at the link.