 On December 1, 1940 Tachikawa was elevated to city status.On May 12, 2011, a robbery of the largest amount of money in Japanese history took place in the city.On that day at 3 a.m., two men wearing masks broke into the office of a security company, bound the sole security guard, beat him until he revealed the code to the company's vault, and then made off with 70 bags of cash containing ¥604 million.