GGR Ishikiriba 100 Hiroshima 2027

GGR Ishikiriba 100 2027 is an unusually demanding 100K loop trail challenge on Kurahashi Island, near Kure in Hiroshima Prefecture. Its course winds around a former stone quarry overlooking Japan's Seto Inland Sea. Rather than crossing a long point-to-point route, runners repeatedly tackle a steep, compact circuit, watching the landscape change from daylight to sunset, darkness and the following morning.

Course and format

The organiser specifies 35 laps of approximately 2.9km, or roughly 101.5km in total. Each lap climbs around 287m, adding up to more than 10,000m of ascent for a full finish. Approximately 90% of the course is unpaved. The loop format lets participants return to the same support area frequently and adjust food, clothing and pacing between circuits. Expect substantial cumulative fatigue despite the modest length of each individual lap.

The race deliberately welcomes athletes who may not complete all 35 laps. Stopping short is not automatically disqualification: the organiser records the distance covered and issues a distance certificate, while full finishers receive a completion certificate. Only finishers qualify for the advertised ITRA four points and UTMB Index 100K recognition.

Race weekend and safety

The Sunday 21 February 2027 programme lists the venue and car park opening at 06:30 JST, on-site check-in from 07:00, a course briefing at 08:45 and the race start at 09:00. The 30-hour limit ends at 15:00 on Monday 22 February. Laps counted are those completed through the timing gate before the deadline. There is no conventional intermediate distance cut-off.

Entrants must be at least 18. Bring a headlamp, waterproof jacket and trousers, warm clothing, drinking cup, heat-resistant cup and health-insurance identification. The organiser also recommends personal food, water, emergency supplies and gaiters for sandy ground. Trekking poles are prohibited, and sleeping is restricted to designated areas. Runners must give way to hikers, respect the natural environment and follow instructions at ropes and narrow sections.

Practical preparation

The event base is Hoshiakari Yamabiko, at the former Katsurahama quarry on Kurahashi Island. The organiser limits entries to 100, so early registration is sensible. Parking gates do not open before 06:30; do not assume early vehicle access. The shared lap-side aid area allows frequent refuelling, but runners should confirm the latest supplies and personal support rules before travelling. The organiser may change or cancel the event for safety reasons, and individual entry cancellations are non-refundable.