Tatsumaru Pass

Overview

Tatsumaru Pass is a category 3 climb in Japan, running 11.2 km from base to summit. It starts at 361 m and tops out at 812 m, giving a net elevation gain of 451 m. On paper that reads as a moderate, mid-length ascent, and the 4.04% average gradient supports that first impression.

The number that changes the story is total ascent: 803 m of climbing against only 451 m of net gain. That 352 m difference is elevation you gain and give back along the way — the climb undulates rather than rising in a single clean line. In practice you do roughly 78% more climbing than the net figure suggests, and every metre lost on a descent has to be re-earned. Treat this as an 803 m effort, not a 451 m one.

How the Gradient Unfolds

A 4.04% average is an accounting artifact here. Because the road repeatedly drops and climbs again, the flat and downhill sections drag the average down and mask the pitches that actually hurt. The steepest ramp bites at 19.16% — steep enough to force you out of the saddle and blow apart any rhythm you had settled into.

• Flatter and downhill recovery sections where you can eat, drink, and reset
• Repeated short climbs that stack fatigue through the middle of the ascent
• A steepest ramp reaching 19.16%, well above anything the average hints at

Pacing Notes

On an undulating climb like this, chasing even speed is a trap: you overspend on every rise trying to hold a number, then coast the descents. Aim for even effort instead. Hold a steady, controlled output on the climbing pitches and let your speed rise freely on the flats and descents — that is where you recover for free.

Anchor that effort to your sustainable power output so the short ramps don't push you into the red early. If you don't know your ceiling yet, run the numbers through the FTP estimator before you ride and set a target you can actually hold across all 11.2 km.

Gearing

Your gearing should be dictated by the steepest ramp, not the gentle average. At 19.16%, a standard road setup will have you grinding at low cadence and shredding your legs before the summit. Run a compact (50/34) or sub-compact chainset paired with a wide-range cassette — 34×32 or 34×34 gives you the bailout gear to spin the steep pitches instead of muscling them. Check your chainring and cassette before the ride; discovering you're under-geared on a 19% wall is not the time to find out.

Summary

• Length: 11.2 km
• Average gradient: 4.04%
• Maximum gradient: 19.16%
• Net elevation gain: 451 m
• Total ascent: 803 m
• Category: 3

Tatsumaru Pass rewards riders who read past the average. Pace to effort, gear for the 19.16% ramp, and respect the 803 m of total climbing hidden inside a modest net gain, and this category 3 becomes a manageable, satisfying day out.