Kozai

Weekday departures: 62/day in the available timetable data · Sat & holiday departures: 62/day in the available timetable data

Earliest / latest departure in the available data (weekday): 5:48 / 23:37

Busiest hour in the available data: 7:00–8:00 (6)

0:00 ─ 23:00

Figures are typical departures in the timetable data, not a live service count.

Timetable data as of 2 May 2026.

The timetable data is incomplete for some or all lines at this station, so the weekday and Sat & holiday figures are departures in the available timetable data, not totals.

Lines where the timetable data is incomplete:

• Yosan Line: one direction only
• Yosan Line: timetable covers only part of the line

• Yosan Line: Takamatsu (Kagawa) ⇄ Kinashi

Kōzai Station opened on 27 January 1952 as an added stop on the existing Yosan Main Line, operated by Japanese National Railways. For much of the JNR era it was treated almost as a provisional halt, with most local trains passing through, though a passing loop completed on 19 November 1956 gave it two platforms and two tracks. Until double-tracking advanced further west in 1967 the station stood at the western end of the double-track section, where a considerable number of trains made operational stops to let others pass; after the Kōzai–Kinashi section was double-tracked on 22 September 1967 most trains passed through again, until late-JNR electrification brought a sharp rise in stopping services. JNR's 1987 privatisation transferred the station to JR Shikoku, where it carries station number Y01. Two staggered side platforms serve local Yosan Line trains and a portion of Dosan Line locals that originate at Takamatsu.

During the long JNR period when few trains stopped here, some next-station signs at neighbouring Takamatsu Station were written in two tiers as "Kinashi (Kōzai)", relegating Kōzai — the station actually adjacent to Takamatsu — to a parenthesis beneath the stop beyond it.