By crossing into Kingite territory, the British had declared war. Both sides now fought for control of the lower Waikato River – the main route for supplies and communication. Imperial troops soon had the advantage, winning the high ground known as the Koheroa Ridge.
The British troops were supported by a fearsome flotilla of armoured gunboats and smaller barges. At Te Paina (aka Mercer) you can see a turret from one of the gunboats, the Pioneer, with the Koheroa ridge forming a half-circle in the distance.