It is a commonly repeated misconception that Singapore's famous large-calibre coastal guns were ineffective against the Japanese because they were designed to face south to defend the harbour against naval attack and could not be turned round to face north. In fact, most of the guns could be turned, and were indeed fired at the invaders. However, the guns—which included one battery of three weapons and one with two guns—were supplied mostly with armor-piercing shells (AP) and few high explosive (HE) shells. AP shells were designed to penetrate the hulls of heavily armoured warships and were mostly ineffective against infantry targets. Military analysts later estimated that if the guns had been well supplied with HE shells the Japanese attackers would have suffered heavy casualties, but the invasion would not have been prevented by this means alone. Percival incorrectly guessed that the Japanese would land forces on the north-east side of Singapore, ignoring advice that the north-west was a more likely direction of attack (where the Straits of Johor were the narrowest and a series of river mouths provided cover for the launching of water craft). This was encouraged by the deliberate movement of enemy troops in this sector to deceive the British. As such, a large portion of defence equipment and resources had been incorrectly allocated to the north east sector, where the most complete and freshest formation—the British 18th Division—was deployed, while the incomplete Australian 8th Division sector with just two brigades had no serious fixed defensive works or obstacles. To compound matters, Percival had ordered the Australians to defend forward so as to cover the waterway, yet this meant they were immediately fully committed to any fighting, limiting their flexibility, whilst also reducing their defensive depth. The two Australian brigades were subsequently allocated a very wide frontage of over and were separated by the Kranji River. Yamashita had just over 30,000 men from three divisions: the Imperial Guards Division under Lieutenant-General Takuma Nishimura, the 5th Division under Lieutenant-General Takuro Matsui and the 18th Division under Lieutenant-General Renya Mutaguchi. Also in support was a light tank brigade. In comparison, following the withdrawal, Percival had about 85,000 men at his disposal, although 15,000 were administrative personnel, while large numbers were semi-trained British, Indian and Australian reinforcements that had only recently arrived. Meanwhile, of those forces that had seen action during the previous fighting, the majority were under-strength and under-equipped. In the days leading up to the Japanese attack, patrols from the Australian 22nd Brigade were sent across the strait to Johor at night to gather intelligence.