Old Assembly Block of the Okayama Prefectural Government Office

The Low Building Beside the Tall One

The Okayama Prefectural Assembly Hall Old Wing (岡山県庁議会棟旧館, Okayama-kenchō Gikaitō Kyūkan) is a three-storey reinforced concrete building in Uchisange, Kita Ward, Okayama City, completed in 1957 as part of Kunio Maekawa's prefectural office complex and entered on Japan's register of Tangible Cultural Properties on 3 December 2024.

It sits southwest of the main office block, linked to it by a covered bridge corridor. Where the main building rises nine storeys and announces itself in black glass, this one stays low and runs horizontally. The pairing is deliberate, and the contrast between the two is the reason both were registered.

The Agency for Cultural Affairs records it as reinforced concrete, three storeys above ground and one below, with a building area of 1,073 square metres and an attached connecting corridor. Its registration number is 33-0371.

The word old in its name is administrative rather than poetic. A new assembly wing was added to the complex in September 1980, and the original 1957 structure took the qualifier to distinguish it. Only the 1957 building carries the registration.

An Assembly Chamber for a New Constitution

Okayama's previous prefectural office at Tenjinyama burned in the air raid of June 1945. The prefecture worked from a converted navy clothing depot until November 1954, when it resolved to rebuild inside the grounds of Okayama Castle. Kunio Maekawa (1905 to 1986) received the commission, and in January 1957 the main block and the assembly chamber were completed together as a single undertaking.

That simultaneity matters. Japan's post-war constitution had reorganised local government barely a decade earlier, giving prefectural assemblies real authority for the first time. Building the chamber as an equal partner to the administrative block, rather than tucking it inside, was a statement about where power was supposed to sit. The prefecture's own registration assessment describes the complex as the architectural expression of post-war democracy.

Maekawa had studied under Le Corbusier in Paris for two years after graduating from Tokyo Imperial University in 1928, then worked for Antonin Raymond before opening his own office in 1935. Okayama was the first government commission of his career, and he approached the whole site as one composition rather than a collection of buildings.

The Third Floor Steps Out

The most distinctive move here is at the top. The third storey projects beyond the wall line on all four sides, so the building reads as a slab hovering over its own base. Under that overhang runs a continuous balcony.

The balcony parapet is filled with hollow bricks, perforated ceramic units set in an unbroken line that turns each corner without stopping. Prefectural guides describe the arrangement as drawn in a single stroke, borrowing the term used for calligraphy written without lifting the brush. Standing at the southwest corner, you can follow that line around and understand what they mean.

The hollow brick itself was developed by Maekawa's office for the Kanagawa Prefectural Library, then under construction. Its holes are cut unusually deep to shade the interior, and their inner faces are glazed so that light bounces off them and travels into the rooms behind. The same units appear on the main block, the east wing and the connecting corridor.

Everything else follows the vocabulary established next door. The frame is left as struck concrete. Window frames are black. Orange special hollow bricks provide the one warm accent. Set beside a nine-storey neighbour clad in curtain walling, the three-storey building holds its own by insisting on the horizontal.

Why the Corridor Matters

Visitors tend to photograph the buildings and ignore what joins them. At Okayama the connection is arguably the more interesting subject.

A covered bridge corridor links the assembly wing to the main block. Above the main building's piloti, another corridor projects north in a U shape, sheltering the approach from the street. Walk the sequence and you move through open air, under cover, across the bridge and indoors without ever encountering a hard threshold. The registration assessment calls this a plan in which outdoor space flows into indoor space, and that flow is the design idea holding the site together.

The complex was selected by DOCOMOMO Japan in 2016 as a significant work of the modern movement in Japan. One of the four criteria cited concerns environmental formation, meaning attention to plazas and the grouping of buildings rather than individual objects. The relationship between the assembly wing, the main block and the courtyard between them is what earned that particular mark.

A seismic strengthening programme covering the main building and the assembly wing was completed in March 2024, nine months before the registration was gazetted. The prefecture chose to retrofit rather than replace, and the design was reproduced as part of the work.

Seeing It in Person

The exterior can be viewed at any time from within the prefectural office grounds, which are not gated. The southwest elevation, where the projecting third floor and its brick balcony read most clearly, is the one to look for. Photography from the grounds and surrounding streets presents no difficulty.

Interior access is another matter. This is a working legislative building, and it does not admit casual visitors. The prefecture's free guided tour of the office complex has previously taken participants into the assembly wing, though the published itinerary has since been shortened, so the route on any given date is worth confirming when you book.

The tour runs roughly ninety minutes for about ten people at no charge, beginning with a short slide presentation on Maekawa before the walk. Applications open on the first day of each month through the Okayama Prefecture electronic application service and close seven days ahead. The building control division handles group bookings of ten or more on 086-226-7504.

Prefectural offices close on weekends and public holidays. From JR Okayama Station, buses bound for Asahigawasō reach the Kenchō-mae stop in about ten minutes; the walk takes around twenty-five. Visitor parking on site costs 100 yen per hour, and the ground floor of the main building next door has a public canteen and an exhibition corner on Maekawa's work.

Okayama Castle and the Kōrakuen garden lie across the Asahi River a short walk away. The Prefectural Library faces the site, and two more Maekawa buildings, the Hayashibara Museum of Art and the Tenjinyama Cultural Plaza, are within walking distance.