Oyodogawa Gakushukan Butterfly Room (大淀川学習館 自然楽習園 チョウのへや)

The Oyodo learning centre (大淀川学習館) opened in 1995, regional broadcaster UMK says; Japanese Wikipedia gives 28 March 1995. The City of Miyazaki describes it as the symbolic facility for the cleaning-up of the Oyodo and for learning about the river: with the outdoor "Waterside School" and "Satoyama School", it forms an environmental education complex. It is run by the Miyazaki Cultural Promotion Association (宮崎文化振興協会). The butterfly room belongs to the "Shizen Rakushūen" exhibition space.

Attendance was about 180,000 visitors a year until 2019, then fell with the pandemic to about 100,000 in recent years, according to broadcaster MRT. In February 2026 the city proposed, in a review of its public facilities, to close the centre, moving part of its functions to the Miyazaki Science and Technology Museum, because of the deterioration of the building and exhibits and the cost of works. After a public consultation held from 25 February to 27 March, with 66 comments on this centre, it announced on 8 May 2026 that the centre would finally be kept. MRT adds that operation is to continue for at least five years, and the city is studying cost cuts, minimal works and the introduction of an entrance fee.

The operator describes the room as "glass-walled" (ガラス張り) and left without air conditioning, which keeps the temperature close to the outside; it stresses that it is unusual in Japan for a butterfly-release facility not to be turned into a heated greenhouse. Its 2022 teaching sheet shows, under the caption "centre of the Rakushūen", a tall room whose glass walls and a glass cupola with ring-shaped ribs let the sky and hills show through, with plants in the foreground. A 2018 visitor speaks of a "large glass room", and the 2026 local press of a "large greenhouse" (大温室).

On the aerial orthophoto of the Geospatial Information Authority of Japan, a circular cupola with concentric ribs, about twenty metres across, ends the south side of the building; identifying it with the butterfly room rests on that shape, which matches the operator's photograph. A neighbouring observation corner, a large breeding cage, shows stick insects, grasshoppers and other insects according to the season.

According to the operator, the room shows an average of 50 to 200 butterflies all year, mostly individuals bred and reproduced on site, favouring species of the Oyodo valley; eggs, caterpillars and chrysalises are also shown according to the season. A host-plant planting, the "first food-plant garden", is named on a photograph of the sheet. The 2026 local press counts about 6,000 butterflies a year, 90% of them born in the centre; the keeper explains that the great difficulty is making the plants flower when the butterflies become adults, since nectar is their food.

Special displays present the ōmurasaki, Japan's national butterfly, and the tsumabeni-chō, whose northern limit is said to lie in southern Kyūshū: both live in the valley but are rarely seen near the centre. The rest of the centre shows, among other things, river fish including the akame, newts and an albino eel, as well as seasonal exhibitions.

The centre stands on the bank of the Oyodo, in the central part of Miyazaki; the bus stop "Ōyodogawa Gakushūkan-mae" is one minute away on foot, by a footbridge with a lift, and Miyazaki-jingū station about ten minutes by car. Beyond the butterfly room, a "river theatre" shows a 3D video of about ten minutes, according to a 2018 visitor, and the neighbouring "Waterside School" supplies the keepers with the crabs and shrimps of their exhibitions.

According to the Jalan reviews, a visit most often takes one to two hours and admission is free; the city confirmed in May 2026 that it is studying an entrance fee. The Aoshima Subtropical Botanical Garden, already in the catalogue, is about 17 km away, and Miyazaki-jingū shrine about 2 km.