The two countries are planning their first foreign and defense ministerial meeting, dubbed 2+2, in India for late November, hoping to pave the way for an Indian summit next month between Japanese Prime Minister Shinzo Abe and his Indian counterpart Narendra Modi.
The new move will extend existing Japanese policy -- in coordination with the U.S. -- of checking China's military expansion, specifically calling for a "free and open Indo-Pacific," as well as maintaining maritime order based on the rule of law.
The two countries upgraded relations when Modi and Abe met in 2014, rebranding their bilateral ties as a "Special Strategic and Global Partnership."
Although the four have not held joint military exercises under Quad, their respective foreign ministers met for the first time on the sidelines of a U.N. General Assembly gathering in late September, a sign that the alliance may be increasing the level of cooperation.
If Quad military drills do take place, Japan will likely need to play the role of intermediary between India and the U.S., coaxing the former into a more definitive stance.