Hakozaki Line

From Nakasu-Kawabata, where it diverges from the curving Kuko (Airport) Line, the Hakozaki Line runs north directly beneath Meiji-dori, passing near the Fukuoka Prefectural Government Office, Kyushu University Hospital and Hakozaki-gu shrine, and crossing the former Hakozaki campus of Kyushu University before reaching Kaizuka, the terminus of the Nishitetsu Kaizuka Line (the former Miyajidake Line). For almost its entire length the route closely follows roads once used by the Nishitetsu Fukuoka city trams, which were abolished in the 1970s. Throughout its history the line has been operated jointly with the Kuko Line: through trains run from Kaizuka onto the Kuko Line toward Tenjin, Nishijin and Meinohama, so that passengers can travel from the Hakozaki Line into central Fukuoka and on toward Fukuoka Airport without changing trains.

The line opened on 20 April 1982 as Line 2, with an initial section between Nakasu-Kawabata and Gofukumachi. On the same day, through-service began with Line 1 — today's Kuko Line — which had just been extended from Tenjin to Nakasu-Kawabata, immediately linking the new line into the city-centre network. This first stretch was short, but it established the operating pattern of joint running with Line 1 that has defined the Hakozaki Line ever since.

Construction then advanced northward in stages. On 27 April 1984 the line was extended from Gofukumachi to Maidashi-Kyudai-byoin-mae, bringing it to the Kyushu University Hospital district. On 31 January 1986 the next section opened, from Maidashi-Kyudai-byoin-mae to Hakozaki-Kyudai-mae. Finally, on 12 November 1986, the last segment from Hakozaki-Kyudai-mae to Kaizuka opened, completing the line in its present 4.7 km form and connecting the subway with the Nishitetsu Kaizuka Line at its northern end.

On 3 March 1993 the route was given the nickname “Hakozaki Line,” the name by which it is generally known today. Later changes were chiefly operational rather than structural: the Hayakaken contactless IC card was introduced at all stations on 7 March 2009, and on 2 March 2011 station numbering was displayed across the line together with the Kuko and Nanakuma lines. In November 2024 the new 4000 series trains entered service, beginning the replacement of the line's oldest stock.

A long-discussed possibility was a through-service onto the Nishitetsu Kaizuka Line, with which the Hakozaki Line connects at Kaizuka. The idea dated back to a 1971 transport-council report and was studied repeatedly from 2007 onward, with various schemes for running trains between the Nishitetsu line and the subway. The plans foundered on cost: the heavy investment needed to upgrade the Nishitetsu line and subway against the limited time savings made most options uneconomic. In January 2021 it was reported that Fukuoka City had calculated a cost-benefit ratio of just 0.42 — far below the break-even value of 1 — for the latest plan, and the project was set to be frozen while leaving the door open in principle.

Today the Hakozaki Line is worked entirely by Fukuoka City Transportation Bureau trains — the 1000N, 2000N and 4000 series — which it shares with the Kuko Line; the JR Kyushu trains that through-run onto the Kuko Line do not enter the Hakozaki Line. Daytime service alternates roughly every seven to eight minutes between trains that run only within the Hakozaki Line, between Kaizuka and Nakasu-Kawabata, and trains that continue through onto the Kuko Line toward Nishijin, Meinohama and beyond. Short though it is, the line provides a direct subway link between the Hakozaki district, the Kyushu University Hospital area and central Fukuoka, and connects with the Nishitetsu Kaizuka Line at its northern terminus.

• 198220 April: Line 2 opens between Nakasu-Kawabata and Gofukumachi; on the same day through-service begins with Line 1 (now the Kuko/Airport Line), just extended from Tenjin to Nakasu-Kawabata.
• 198427 April: the line is extended from Gofukumachi to Maidashi-Kyudai-byoin-mae.
• 198631 January: the section from Maidashi-Kyudai-byoin-mae to Hakozaki-Kyudai-mae opens.
• 198612 November: the final section from Hakozaki-Kyudai-mae to Kaizuka opens, completing the line in its present 4.7 km form.
• 19933 March: the nickname “Hakozaki Line” is officially set.
• 20097 March: the Hayakaken contactless IC card is introduced at all stations on the line.
• 20112 March: station numbering is displayed across the line, together with the Kuko and Nanakuma lines.
• 2021January: Fukuoka City is reported to have calculated a cost-benefit ratio of 0.42 for through-service onto the Nishitetsu Kaizuka Line, far below break-even, and the plan is set to be frozen.
• 202429 November: the new 4000 series trains enter revenue service, beginning replacement of the line's oldest stock.