Kojiri Pass

Overview

Kojiri Pass is a Category 2 climb in Japan that runs for 21.9 km from a valley floor at 163 m to a summit at 838 m. The headline figure is a net elevation gain of 675 m, which over that distance produces a modest average gradient. On paper this looks like a long, steady drag rather than a wall — a climb you settle into rather than survive.

That impression is misleading. The net gain of 675 m sits well below the total ascent of 1,136 m, a gap of 461 m. That difference is climbing you do and then give back on descents and false flats before climbing again. Undulation of this size means the road repeatedly kicks up and rolls back down, so your legs accumulate far more vertical work than the net profile suggests. Pace it like a 675 m climb and the extra 461 m will find you.

How the Gradient Unfolds

The average gradient is diluted by every descending and flat metre in that undulating profile, so it tells you almost nothing about the hard sections. The real work is concentrated in short, sharp pitches, culminating in a maximum gradient of 20.48%.

• Flatter and recovery sections where the road dips or levels between rises
• Repeated short climbs that reset your effort again and again across the 21.9 km
• A steepest ramp reaching 20.48% — brief, but enough to spike your heart rate and empty a light gear

Pacing Notes

On a smooth, steady climb you can hold even speed and even effort at once. Kojiri Pass does not allow that. Because the gradient constantly changes, chasing a constant speed forces you far over threshold on every ramp and lets you coast on every dip — a wasteful, spiky ride.

Pace by effort instead. Anchor to your sustainable power output and let speed rise and fall with the road: back off slightly as the gradient steepens so you do not blow up on the 20.48% ramp, and resist hammering the flatter recovery sections. If you do not know your ceiling, run the FTP estimator before you go, then ride the whole 21.9 km just under it.

Gearing

The steepest gradient governs your gearing choice, and 20.48% demands a low bailout gear. Fit a compact (34-tooth inner) or a sub-compact chainset, paired with a wide-range cassette — a 34×32 or 34×34 gives you a spinnable escape ratio for the worst ramp without wrecking your cadence. With 1,136 m of total ascent and repeated pitches, you will lean on that low gear more than once. Check your setup before the ride; a chain barely reaching the largest sprocket is not something to discover mid-climb.

Summary

• Length: 21.9 km
• Average gradient: 3.08%
• Maximum gradient: 20.48%
• Net elevation gain: 675 m
• Total ascent: 1,136 m
• Category: 2

Kojiri Pass is a deceptive Category 2 climb: a gentle average hiding sharp ramps and 461 m of hidden vertical. Pace by effort, gear low, and treat the whole 21.9 km as the challenge — not just the summit.