The continuous development of Johor Bahru was, however, halted when the Japanese under General Tomoyuki Yamashita invaded the town on 31 January 1942. As the Japanese had reached northwest Johor by 15 January, they easily captured major towns of Johor such of Batu Pahat, Yong Peng, Kluang and Ayer Hitam. The British and other Allied forces were forced to retreat towards Johor Bahru; however, following a further series of bombings by the Japanese on 29 January, the British retreated to Singapore and blew up the causeway the following day as a final attempt to stop the Japanese advance in British Malaya. The Japanese then used the Sultan's residence of Bukit Serene Palace located in the town as their main temporary base for their future initial plans to conquer Singapore while waiting to reconnect the causeway. The Japanese chose the palace as their main base because they already knew the British would not dare to attack it as this would harm their close relationship with Johor.