During the Flagstaff War Kawiti and Heke appear to have followed a strategy of drawing the colonial forces into attacking a fortified pā, from which the warriors could fight from a strong defensive position that was secure from cannon fire. The word "pā" means a fortified strong point near a Māori village or community. They were built with a view to defence, but primarily they were built to safely store food. Puketapu Pā and then Ohaeawai Pā were the first of the so-called "gunfighter "pā"", built to engage enemies armed with muskets and cannons. A strong, wooden palisade was fronted with woven flax leaves ("Phormium tenax") whose tough, stringy foliage absorbed much of the force of the ammunition. The palisade was lifted a few centimetres from the ground so muskets could be fired from underneath rather than over the top. Sometimes there were gaps in the palisade, which led to killing traps. There were trenches and rifle pits to protect the occupants and, later, very effective artillery shelters. They were usually built so that they were almost impossible to surround completely, but usually presented at least one exposed face to invite attack from that direction. They were cheap and easily built—the L-Pa at Waitara was constructed by 80 men overnight—and they were completely expendable. The British repeatedly mounted often lengthy expeditions to besiege a "pā", which would absorb their bombardment and possibly one or two attacks, and then be abandoned by the Māori. Shortly afterwards, a new "pā" would appear in another inaccessible site. "Pā" like these were built in the dozens, particularly during the First Taranaki War, where they eventually formed a cordon surrounding New Plymouth, and in the Waikato campaign. For a long time, the modern "pā" effectively neutralised the overwhelming disparity in numbers and armaments. At Ohaeawai Pā in 1845, at Rangiriri in 1863 and again at Gate Pā in 1864, British and colonial forces discovered that frontal attacks on a defended "pā" were extremely costly. At Gate Pā, during the 1864 Tauranga Campaign, Māori withstood a day-long bombardment in their underground shelters and trenches. The palisade destroyed, the British troops rushed the "pā" whereupon Māori fired on them from hidden trenches, killing 38 and injuring many more in the most costly battle for the Pākehā of the New Zealand Wars.