Hirayu Pass

Overview

Hirayu Pass is a Category 1 climb in Japan, running 11.1 km from base to summit. It gains 781 m of net elevation, starting at 909 m and topping out at 1,690 m. At an average gradient of 7.01%, it sits firmly in the range where a Category 1 classification is earned by length and sustained pitch rather than by any single wall.

The number that matters most here is the gap between net gain and total ascent. You climb 781 m in net terms, but the road actually makes you ascend 1,076 m — a 295 m difference. That extra 295 m of climbing gets clawed back through descents and dips along the way, meaning this is not a clean, one-directional grind. You will pay to climb ground you then give away, and that undulation makes the effort harder than the average gradient alone suggests.

How the Gradient Unfolds

An average of 7.01% is a blend, not a description. Because 295 m of ascent is spread across recovery dips, the true climbing sections are steeper than 7.01% to compensate for the flatter and downhill stretches. Expect the road to punch above its average wherever it climbs.

• Flatter or descending sections where the road gives back elevation — brief recovery, but they inflate the effort accounting.
• Repeated short climbs stacked between those dips, each steeper than the 7.01% average implies.
• A steepest ramp that spikes well above the average — hold power in reserve for it.

Pacing Notes

On an undulating climb like this, even-effort pacing beats even-speed pacing. Chasing a constant speed forces you to spike power on every ramp and coast through every dip, burning matches you can't afford to lose. Instead, hold a steady sustainable power output and let your speed rise and fall with the terrain — faster on the shallow bits, slower on the ramps, but the effort constant.

Anchor that target below threshold so the steep pitches don't blow you up. If you don't know your number, run the FTP estimator before you ride and set a ceiling you can hold for the full 11.1 km.

Gearing

Gear for the steepest ramp, not the average. On a Category 1 climb of this length, a compact (50/34) or sub-compact chainset paired with a wide-range cassette gives you the low gears to keep cadence when the road bites. Something in the range of 34×32 or 34×34 lets you spin rather than grind through the steep pitches and the repeated short climbs.

Check your setup before the ride. Confirm your smallest chainring and largest sprocket, and make sure the drivetrain shifts cleanly into that bottom gear — you will need it.

Summary

• Length: 11.1 km
• Average gradient: 7.01%
• Net elevation gain: 781 m
• Total ascent: 1,076 m
• Category: 1

Hirayu Pass rewards riders who respect the difference between its net gain and its total ascent. Pace to a sustainable power target, gear low enough for the steep ramps, and let the undulation work with you rather than against you over the full 11.1 km.