The Johore Battery comprised three guns. They were part of a group of twenty nine large coastal guns installed in Singapore in the 1930s.
The Johore Battery's three weapons were among Singapore's largest coastal guns. They were known as 15-inch guns, because 15 inches (38 cm) was the diameter of the shell they fired. Their gun barrels were 16.5 metres long and the shells stood 1.5 metres high. The guns were capable of hurling these shells at battleships over twenty miles away.
They were originally called "monster guns" when tested in England in 1934, before being sent to Singapore. When World War II started, there were only seven of these defending the coasts of the British Empire. Two were near Dover in England, and five in Singapore. Besides the Johore Battery, Singapore also had two 15-inch guns at Buona Vista Battery. They were located at the junction of Ulu Pandan and Clementi Roads, in the West of the island.
Each of Johore's Battery's guns had its own ammunition buker. These were about 500 metres apart, arranged in a line that stretched from the present site onto what are now the runways of Changi Airport. Though these guns were originally intended to stop an attack from the sea, two of Johore Battery's guns could turn around and fire to the rear, towards Johor Bahru. The third, the one located at this site, could only fire out to sea.
From 5th to 12th February 1942, the two guns of the Johore Battery that could turn around fired landward in Singapore's defence. They shelled Japanese infantry positions from Johor Bahru, just across the Causeway, eastwards to the area North of Tanjong Punggol. They also joined in the battles for Bukit Timah Road and Pasir Panjang. The guns of Johore Battery fired 194 rounds before their demolition by the British on the night of 12th February. This demolition, and the postwar upgrading of Changi aerodrome, means all the remains are the underground tunnels on this site, which once housed ammunition and power plants.