Operation Brasstacks was India’s largest-ever military exercise, conducted from November 1986 to March 1987 in Rajasthan. Involving nearly 500,000 troops, tanks, and air support, this unprecedented show of strength aimed to test India’s new mechanized warfare strategies and operational readiness. The sheer scale and proximity to the Pakistan border stunned the world and sent shockwaves through Islamabad, which feared an imminent invasion.