Mizukoshi Pass

Overview

Mizukoshi Pass is a category 3 climb in Japan that runs 12.4 km from base to summit. It starts at 86 m and tops out at 524 m, for a net elevation gain of 438 m. On paper that reads as a steady, moderate ascent, and the category reflects that: this is a substantial ride, but not a monster.

The net gain, however, tells only half the story. The climb records 729 m of total ascent against just 438 m of net gain. That 291 m gap means the route sheds and re-earns roughly 291 m of descending across its length. You are not climbing one clean ramp; you are climbing over rollers, giving back altitude, then taking it again. That undulation makes the effort feel harder than the average gradient suggests, because every dip forces you to rebuild momentum and re-attack the next rise.

How the Gradient Unfolds

The 3.54% average gradient is a blend, not a constant. With 291 m of hidden descending baked in, the true climbing pitches are noticeably steeper than the average, and the steepest ramp bites at 17.52% — more than five times the average. Expect the road to swing between easy spinning and short, sharp efforts rather than settling into one rhythm.

• Flatter and downhill recovery sections where you carry speed and spin easily
• Repeated short climbs that stack up to the 729 m of total ascent
• A steepest ramp near 17.52% that demands your lowest gear

Pacing Notes

On an undulating climb like this, chase even effort, not even speed. Hold a steady, sustainable power output through the steep pitches and let your speed rise on the descents rather than surging to hold a target pace uphill. Overcooking the 17.52% ramp early will cost you on the many rises that follow. If you do not know your sustainable number, run the FTP estimator first and set your ceiling below it so the repeated short climbs do not drain you before the 524 m summit.

Gearing

The steepest gradient governs your gearing here, and at 17.52% you want range to spare. Fit a compact or sub-compact chainset paired with a wide-range cassette — a 34×32 or 34×34 will let you keep a sustainable cadence on the sharpest ramp instead of grinding it out. Check your setup before the ride; discovering you are undergeared on a 17.52% pitch is not a mid-climb problem you can fix.

Summary

• Length: 12.4 km
• Average gradient: 3.54%
• Maximum gradient: 17.52%
• Net elevation gain: 438 m
• Total ascent: 729 m
• Category: 3

Mizukoshi Pass is a deceptive category 3: a gentle average masking 291 m of hidden climbing and a ramp that hits 17.52%. Pace it by effort, gear it for the steepest pitch, and it rewards you with a summit at 524 m.