Most of the far northern dialects (Tōhoku dialects and Hokkaidō) and far southern dialects (notably Okinawan Japanese) and the Ryukyuan languages (the other Japonic languages) have also mostly merged these down to one sound.
In the current Tokyo dialect, on which the modern standard Japanese language is based, and also in the widely spoken Kansai dialect, only two sounds are distinguished, as represented in the Hepburn (ji, ji, zu, zu) and Kunrei (zi, zi, zu, zu) romanization systems.