Several things about Taipei County's Sandiaoling Waterfall (三貂嶺瀑布) make it stand out in an area so rich in fine waterfalls. The approach to the fall – either up the beautiful lushly foliated glen or down a log ladder hung over a thrilling, sheer rock face – is especially memorable, the area is refreshingly free of handrails and surfaced paths, and the waterfall is impressively high (about forty meters). But what makes the waterfall really stand out is the huge overhang behind it (known locally as Moon Cave), allowing hikers to walk behind the curtain of water, and yes – even spend the night there!

Sandiaoling Waterfall and its two impressive companion falls, one above it and one below, are the centerpiece of one of the finest easier walks in Taipei County. The entire trail can be comfortably walked in three hours or so, and apart from ascending the rock faces beside Sandiaoling and Niyao Waterfalls (which have been much simplified recently with the addition of ladders) the hike is a simple one, mostly level or gently climbing, with no steep ascents.

Logically enough, the Sandiaoling Waterfall Walk starts at the tiny hamlet of Sandiaoling, one of Taipei County's most secluded settlements. Although there is now finally a road of sorts to the village, the main access for visitors remains the railway. Most slow trains along the mainline Taipei to Ilan railway line stop here, as do all trains running along the scenic Pingsi Branch Railway, stopping at Sandiaoling station immediately before veering right off onto the branch railway line up to Pingsi.

Exit the tiny station, which sits alone amongst beautiful scenery in a shallow gorge carved by the Keelung River, and follow the railway tracks southwards, away from Taipei. Keep right just before the bridge over Keelung River as the Pingsi Branch Line veers off from the main line, and follow the branch line tracks into tiny Sandiaoling village.

Turn right just after passing the village's long-abandoned and now half derelict elementary school, and pick up the path, climbing until it levels out, high above the river, passing through mixed woodland and a few large stands of bamboo.

In about twenty minutes, after the woods give way to patches of more open country covered in tall grass, a flat area to the left of the path gives the best view of the first fall, forty-meter-high Hegu Waterfall (合谷瀑布); thick undergrowth below the path means only the top half of the impressive fall is visible these days, but it's still a very impressive sight, especially after heavy rain.The trail crosses the stream about fifty meters above the head of Hegu Waterfall, and dives back into the woods and a deep, steep sided gorge as it approaches Sandiaoling Waterfall itself. Another twenty minutes and the lofty white plume of the waterfall appears through the trees ahead. The wooden viewing platform at the base of the falls is a welcome recent addition, giving a fine view of the water as it plunges well clear of the cliff into a pile of rock at the bottom.

For the best view of the waterfall and the spectacularly overhanging horseshoe-shaped cliff off which the stream hurtles, follow the trail as it climbs high up the side of the gorge below the fall, and turn right along a narrow trail that soon joins the cliff and then lies underneath the overhang, eventually passing right behind the falling water, for a unique view out through the curtain of water and down the gorge.

Following the main trail as it climbs out of the gorge, it soon reaches the bottom of a chunky rope ladder made of thick logs. It's an awkward ascent, but while struggling upwards, it's worth remembering that getting up is a good deal easier than formerly, when hikers had to rely on fixed chains and footholds to scale the cliff.

At the top, a fine surprise awaits in the form of a third waterfall less than a hundred meters upstream from the lofty drop below. Niya Waterfall is an almost perfect, slightly smaller replica of Sandiaoling Waterfall, complete with horseshoe cliff and prodigious overhang (although unfortunately it's not possible to stand behind this fall).

The trail escapes from the ravine made by the waterfall by scaling a metal ladder (again a great improvement, safety-wise on the former ropes and slippery footholds), and in a few meters rather unexpectedly joins a concrete path.

Turn left and in about forty minutes the path leads back to civilization and a road at the tiny settlement of Sinliao. Turn left here and the road finally descends to Shifen, an immensely popular stop-off on the Pingsi branch railway line. Be warned though: the weekend crowds milling around the town and surrounding area are likely to come as a shock after the peace and quiet of this fine walk.