Hakka Pass

Overview

Hakka Pass is a category 4 climb in Japan, running 6.4 km from a valley floor to a modest summit. It starts at 403 m and tops out at 624 m, for a net elevation gain of 221 m. On paper that reads as a gentle warm-up: a short climb with a shallow average pitch. The category and the numbers place it firmly among the easier ascents, but the profile is not as tame as the net figures suggest.

The gap between the two ascent figures is where the real character sits. Net elevation gain is 221 m, yet total ascent is 507 m. That 286 m difference is climbing you do that the net gain never credits you for — you gain height, give some back on descents and dips, then climb it again. On an undulating road like this you pay for more vertical than the start-to-summit math implies, and the repeated changes in gradient tax the legs more than a single steady haul of the same net height would.

How the Gradient Unfolds

The 3.48% average is the least useful number on this climb. An average that low across a road carrying an 18.52% maximum tells you the gradient swings hard from flat to severe. Expect the climb to arrive in pulses rather than one continuous wall, with the steep sections concentrated in short, sharp bursts.

• Flatter and recovery sections where the road eases off or briefly tips downhill — these are what drag the average down.
• Repeated short climbs stacked back to back, which is where the 286 m of "extra" ascent accumulates.
• A single steepest ramp at 18.52% that will spike your effort well above anything the average prepares you for.

Pacing Notes

Do not pace this climb to an even speed. On undulating terrain, holding constant speed means surging power on every ramp and coasting on every dip — a fast way to burn matches. Pace to even effort instead, anchored to your sustainable power output. Let your speed rise on the flatter recovery sections and hold power steady into the steep pitches rather than chasing a number on the display.

The 18.52% ramp is the exception: there you will exceed threshold no matter how disciplined you are, so accept the brief spike and settle back down immediately after. If you do not know your target wattage, run the FTP estimator before you ride so your effort ceiling is a real figure, not a guess.

Gearing

The steepest gradient governs your gearing, and 18.52% is steep enough to demand a bailout gear. Fit a compact (50/34) or sub-compact chainset paired with a wide-range cassette — a 34×32 or 34×34 low gear gives you the cadence to spin the steep ramp instead of grinding it. Check your setup before the ride: confirm the cassette and chainset you have actually deliver that low ratio, because discovering you are over-geared halfway up the 18.52% pitch is a costly mistake.

Summary

• Length: 6.4 km
• Average gradient: 3.48%
• Maximum gradient: 18.52%
• Net elevation gain: 221 m
• Total ascent: 507 m
• Category: 4

Hakka Pass is short and low-category, but the undulation makes it more demanding than its net gain suggests. Pace to even effort, carry a low enough gear for the 18.52% ramp, and treat the total ascent — not the net gain — as the honest measure of the work ahead.