Japanese policy decisions have pushed slowly and gradually toward space security since at least the 1980s. This slow ascent is reflected not just in the history of its security space activity but also in current debates within the Japanese space community. These debates center on incremental changes and focus less on whether Japan should shift its focus toward security and more on how far and fast this shift should take place. The potential that Japan could bring to space partnerships is enormous. This is an ally that has one of the biggest space budgets and is renowned for technological prowess—the country that brought us the bullet train. But the limitations should be understood too.