Japan's largest law firms—Nishimura & Asahi; Nagashima Ohno & Tsunematsu; Mori Hamada & Matsumoto; and Anderson Mōri & Tomotsune—continue to be monoliths in the Japanese market, dominating in the value of their deals as well as on the number of lawyers they employ. But one upstart firm has positioned itself to be a contender, hoping to compete with these firms, which have come to be known as Japan's "big four."