"Riverdance" is returning to Japan. Twenty years on from its debut as an interval in the Eurovision Song Contest in 1994, the Irish step-dancing show that revamped and massively expanded the genre's global appeal is returning to Japan for its sixth tour.

It's hard to overstate the effect that first "Riverdance" performance had on Irish dancing. I grew up doing Irish dancing — it wasn't a popular pastime for boys, and as a style of dancing it was quite rigid as hand movements were forbidden. Outside of Ireland and Irish communities around the world it was about as well known as hurling. But, to borrow a line from the poet W.B. Yeats, Irish dancing "changed, changed utterly" in the wake of "Riverdance."

The current show, which tours Japan in April, is the 20-year celebratory tour. Of course, many of the original cast, including Michael Flatley — famous as much for his waxed chest as his footwork — have long since moved on, but how else has the show changed?

"In some ways a lot, and yet in other ways not at all," Julian Erskine, an executive producer of "Riverdance" told The Japan Times. "The big key numbers are still there as they were in 1995, but with the recent face-lift everything is fresh and vibrant."

Those changes include adding a new dance routine, different stage lighting and some new costumes, Erskine added.

It's worth pointing out that prior to "Riverdance," Irish-dancing costumes included traditional kilts and heavily embroidered dresses. "Riverdance" cleaned out the wardrobe and, depending on your perspective, either liberated it or made it slightly lurid. Either way, the new style helped the performance become a global phenomenon: More than 22 million people have seen the show live.

While the show bills itself as a celebration of Irish music and dance, it's not confined to showcasing Irish culture — tap dance and flamenco also feature — and as a formula it has had great staying power.

"It's simply pure entertainment," Erskine said, "It has great music, exciting choreography and, of course, amazing dancers."

There are no Japanese dancers on this tour but, according to Erskine "Riverdance" has in the past inspired audience members to quit everything in pursuit of Irish dance. This happened to Takayuki Hayashi, who moved to Ireland from Tokyo after seeing the show 15 years ago. Hayashi's efforts paid off — he has danced with the "Riverdance" cast and now runs an Irish dance school in Tokyo. Other schools in Osaka and Yokohama also have their origins in "Riverdance," further evidence that it really is the show that put Irish dancing on the map.

"Riverdance 20 Years" runs from April 3-15 at Tokyu Theatre Orb in Tokyo. It then travels to Toyama, April 18-8; Nagoya April 22-26; and then Osaka, April 28-May 2. For more information, visit riverdance.com/tours/japan or bit.ly/hipjpn.