A marked farm track leads to the Tukituki River, and from there you follow the river’s clear waters upstream. There is no marked track, but the banks of the Tukituki provide interesting and reasonably fast travel. You will need to cross the river though, so this trip is not recommended if the river is running high. 

After around 2–3hr, a large orange track marker indicates the start of Rosvalls Track and a DOC sign confirms that the track leads to Tarn Bivouac. The track is steep but well maintained and provides a direct route to the bushline, which you reach after around two hours of energetic huffing and puffing. Here, from Pt1285, are the first views of Ohuinga and Sawtooth Ridge.

From Rosvalls Track, Ohuinga may appear impossibly far away. Don’t despair, the characterful, dog-kennel-style Tarn Bivouac is only 30 minutes further along Black Ridge.

You can end your trip at Tarn Bivouac, which makes for a cosy night’s sleep and allows commanding views of Hawke’s Bay and ample sun. However, the scramble up Ohuinga is worthwhile.

Follow Black Ridge north over gentle knobs and past sparkling tarns. It’s good travel along the broad, gentle ridge, and eventually the goal looks achievable. There are some impressive slips on the final kilometre to Ohuinga, and steep views down to the Tukituki Valley. At the northern end of Black Ridge and at the very head of the Tukituki River is a saddle and a final 200m ascent to the summit. This ascent is fun, skirting around a scree slope and using snowgrass and tussock to haul up over the steeper sections. There’s a faint foot trail but navigation is straightforward. In summer it doesn’t feel dodgy; however, if ice and snow were present it would be a different trip. 

From the 1686m summit you can see the Manawatū and Hawke’s Bay, and to the north and south are more rugged ridges of Ruahine Forest Park. 

Retrace your steps along Black Ridge to return to the bivouac and Rosvalls Track, happy in the knowledge that no further ascent is required.