From Hokkien 嘉義/嘉义 (Ka-gī).
Ka-gi
- Synonym of Chiayi
1895, John Dodd, “Formosa”, in Scottish Geographical Magazine[1], volume XI, number XI, Edinburgh: T. and A. Constable, page 567:During the eighteenth century Chinese immigrants continued to pour into the country, and soon Hakka and Fo-kienese villages sprang up all along the coast. On their arrival they were sent inland by the local authorities in search of suitable localities outside the territory already cleared by other pioneers. Large towns sprang up in course of time, like Tai-wan-fu with its 200,000 inhabitants, Ka-gi or Ka-i to the west of Mount Morrison, and Chang-hua a little north of lat. 24″, and, in the north, Teckcham, the local name for Hsin-chu, the populous town of Banka with 40,000 inhabitants, and Twa-tu-tia with 20,000 to 30,000.
1915, William Campbell, Sketches from Formosa[2], Marshall Brothers Limited, page 72:Ka-gi city is the place which has come more prominently before our notice in connection with this war scare. The region after which this city takes its name occupies the middle-western part of the Island, and form the largest and most populous of the Formosan counties. We require to travel right through it while visiting the Sek-hwan stations, and although there is an encouraging work going on among the Pi-po-hwan of Ka-gi county, our great desire was to begin stated preaching work in some purely Chinese community there.