パックン岩、延岡

Pakkun Rock (Pakkun-iwa) is a large natural rock formation located on the mid-slope of Mt. Hokodake (1,277 m) in the Kamishikagawa area of northwestern Nobeoka City, Miyazaki Prefecture. Its striking open-jawed shape closely resembles the iconic video game character Pac-Man, and the rock's mouth is wide enough to comfortably fit ten people inside at once. The formation sits within the Sobo-Katamuki-Okue UNESCO Biosphere Reserve, a protected mountain zone on the border of Miyazaki and Oita prefectures known for its geophysical landscapes, sheer granite cliffs, and biodiversity comparable in character to parts of Yosemite.

The broader Mt. Hokodake trail is ecologically significant and home to rare endemic species including the Japanese serow, the purple emperor butterfly (Japan's national butterfly), and plants such as Akebono azaleas (spring) and Tsukubinoki (early summer). Behind Pakkun Rock stands Menboko, a granite monolith measuring 350 metres and recognized as the largest bare rock slab in Japan, also a prominent destination for sport rock climbers. The surrounding forest and river valleys support populations of Genji fireflies, a species increasingly rare across Japan.

The primary visitor experience is the guided trek to Pakkun Rock, which begins at Shishigawa Camping Ground and takes approximately one hour on foot each way. The full circuit of Mt. Hokodake's summit can be completed in three to four hours. Guided trekking tours are operated by the local NPO Himuka Kando Taiken World, with tours meeting at Kagawa Campground.

The highlight of the experience is standing inside the rock's open "mouth" for photographs. Beyond the rock, the trail also passes Hokodake Falls and offers panoramic summit views. Hotel pick-up from Nobeoka City and Nobeoka Station is available through the tour operator for an additional on-site fee.

By car, the Shishigawa Camping Ground trailhead is approximately 1 hour 20 minutes from downtown Nobeoka via National Route 218 and Prefectural Route 214, or 40 minutes from the Kurata Exit of the Northern Nobeoka Road (Route 218). A free car park accommodating up to 15 vehicles is available near the trailhead. There is no nearby public transport to the trailhead, making a car or arranged tour pickup the practical options for most visitors.