Indian Prime Minister Narendra Modi and Japanese Prime Minister Sanae Takaichi signed a historic defence co-development agreement during a summit in New Delhi on July 2, 2026 [1].

The agreement marks a significant shift in security cooperation between the two nations. By moving from procurement to joint development, the countries aim to strengthen their strategic autonomy and military interoperability in the Indo-Pacific region.

The meeting was part of the 16th India-Japan Annual Summit [1]. During the proceedings, Modi addressed Takaichi as his "younger sister" [2]. Officials said the term was used to convey personal warmth and underscore the growing partnership between the two leaders.

This first-of-its-kind defence co-development agreement [1] represents the centerpiece of the diplomatic talks. Along with the security pact, the two nations signed several other memorandums of understanding to bolster economic, and technological ties.

Prime Minister Takaichi is currently on a three-day visit to India [3]. The itinerary focuses on deepening bilateral cooperation across multiple sectors, ranging from infrastructure to maritime security.

The personal rapport between Modi and Takaichi served as a backdrop for the formal negotiations. The use of familial language by the Indian Prime Minister is intended to signal a high level of trust and mutual respect between the two administrations [2].

Both leaders said the partnership is essential for maintaining stability in Asia. The summit concludes a series of high-level diplomatic engagements aimed at aligning the strategic interests of New Delhi and Tokyo.

“India and Japan signed a historic defence co-development agreement.”

The transition from buying equipment to joint development signifies a deeper level of strategic trust between India and Japan. By co-creating military technology, both nations reduce their reliance on third-party suppliers and create a more integrated security architecture to counterbalance regional influence in the Indo-Pacific.