Yanagawa was called "the capital of water" since the Kamachi clan ruled there, and Yoshimasa developed Yanagawa to be a modern town with waterways for transportation and irrigation canals for rice cropping.
蒲池氏が領主だった頃から柳川は「水都」といわれたが、吉政は柳川に交通のための水路や稲作のための用水路を整備し近代的な街作りをした。