The Sculpture Triangle is a handy way of promoting what’s on at Yorkshire Sculpture Park, the Hepworth and around – but there’s something else in it, too.

When is a triangle not a triangle? When you join the dots between four Yorkshire galleries whose collective strength comes in sculptural (but not quite triangular) form it isn’t, strictly speaking. Yes, we’re talking about Yorkshire Sculpture Triangle, a route that leads from Yorkshire Sculpture Park to The Hepworth before heading over to the two main galleries in Leeds (the Henry Moore Institute and Leeds Art Gallery) and back again.

Now, before you dismiss this as a triumvirate ruse dreamed up by a marketing department on a cold, wet, wintery afternoon… Okay, that’s what it is. Of course it is. But sometimes a bit of marketing goes a long way, and, really, it makes sense to link the opening of the Hepworth in 2011, a gallery dedicated to one of Britain’s most celebrated sculptors, with the 500-acre Yorkshire Sculpture Park that’s only 17 miles and a half hour drive away. They are both an important part of what’s on in the area.

“Yorkshire Sculpture Park has always inspired people to visit, but after we opened we noticed that people were moving naturally between the venues here and in Leeds,” says Simon Wallis, the director of The Hepworth, Wakefield. “We had become the new corner; we are the bit that filled in the last side of the triangle.” Despite its proximity to Leeds, YSP did always feel a little isolated: having the Hepworth on its doorstep was one of those “well, duh” moments that made people realize that, actually, it was within 20 miles of three other rather sizeable galleries.

“Every hill and valley became a sculpture in my eyes”

All the sculpture triangle does, really, is point out that fact. “Sculpture is a major component of what we all do here,” says Wallis, “and it made sense for people to get a sense of the strength of the arts in this area.” If you need further persuasion, check the recent joint commission of two major new works by the LA-based (and Leeds born) artist, Thomas Houseago. Timed to coincide with the Yorkshire Festival, the monumental sculptures sit outside Leeds Art Gallery and in the grounds of Yorkshire Sculpture Park respectively, underlining the connections between the two.

But this is not just about being neighbourly. There’s something else at play here, too. Barbara Hepworth was born and bred in Wakefield; the landscape of the West Riding, through which she used to travel with her civil engineer father as he did his rounds, was a direct inspiration for her work. They’d ride around in his car, the young Hepworth feeling like a bird flying up above the valleys, dales and moors. What struck her was the “paradox of the rather grim industrial towns springing out of the magnificent beauty of the West Riding”.

This is what did it for the young Hepworth; “every hill and valley became a sculpture in my eyes”. Her Yorkshire background, she later said, somehow permeated every work of art she ever made. And Henry Moore, another child of Yorkshire and a contemporary of Hepworth, was similarly inspired; the undulating form of his reclining figures surely a result of the hills and moors of Yorkshire being forever imprinted on his mind’s eye.

So, while the Yorkshire Sculpture Triangle is a curiously shaped triangle, put together for pragmatic effect – joining the cultural dots between four like-minded galleries – it does work. It’s a reminder to head out to Wakefield and around and ponder a landscape that was such an inspiration, and a triangle that’s a very curious shape.