The Tokyo sets are replicas of those seen in the movies, albeit ones built by the original designers, who made them in Britain before loading them into 350 Tokyo-bound shipping containers.

This approach has worked in Tokyo’s favour, because the Japanese tour has a Ministry of Magic, a spooky Defence of the Dark Arts classroom and other sets that are not on show in London.

Before the tour, visitors can stop by the Frog Café, inside a replica of Hogwarts’ Great Hall (complete with genuine Yorkstone flooring), where long tables bear the colours of the four houses, and house flags flutter from the ceiling.

A visitor dressed as Hermione approaches me looking concerned – am I aware I’m eating a Slytherin cupcake while sitting at a Gryffindor table?

Worried she’ll cast her Immobulus spell, I beat a hasty retreat to the world’s largest Harry Potter shop, which has 14 sections resembling areas such as Honeydukes sweet shop.

Seven thousand props – wands and costumes included – decorate the store, which is stocked with items unique to Japan, including chopsticks adorned with images of Harry and key rings featuring manga-style depictions of Hermione.

Executive vice-president of Warner Bros Worldwide Tours and Retail Sarah Roots, in Tokyo for the opening, tells me the headbands have been incredibly popular.

“It’s apparently a very Japanese thing – you come in a group and everybody wears matching headbands,” she says.

Several thousand yen lighter, I head for the start of the tour, introduced by Kensho Ono, who voiced Harry Potter for Japanese audiences and appears on a screen above the Hogwarts-worthy doors leading to the main attraction.

I step into the hall containing Hogwarts’ moving staircase. The designers of this set, which is unique to Tokyo, have replicated the hidden mechanisms – every few minutes the stairs rumble to life and change position, under the watchful eye of professors immortalised in the hallway’s moving portraits.

Speaking of which, if you’ve ever dreamed of appearing on Hogwarts’ wall of fame, here’s your chance – visitors can strike a pose at recording stations before their portrait appears on the wall.

Interactivity is a constant – a nod to the Japanese love of live-streaming and selfies.

Visitors can pose in a mock-up of a quidditch court spectator stand, where they’re asked to cheer or boo by staff members. Footage of a quidditch match is then played, interspersed with crowd scenes showing those visitors cheering (or booing) at students chasing the golden snitch.

Wannabe wizards can straddle a broomstick against a green screen to create a clip of themselves soaring over Hogwarts.

At the Backlot Café, approximately halfway through the tour, there are Insta-friendly owl-shaped Hedwig cakes and dishes served on plates in Hogwarts’ house colours, all of which can be washed down with Harry’s beloved non-alcoholic butterbeer – an acquired taste, as is the butterbeer popcorn.

The cafe backs onto an open-air area filled with larger props, including the famous triple-decker bus and the Weasleys’ Ford Anglia, and visitors can pose in both.

Inside a full-size replica of the Dursleys’ No 4 Privet Drive, complete with gnome-dotted lawn, I file through a hallway lined with school certificates awarded to the snivelling Dudley. The kitchen counters heave with the detritus – including chicken bones and a toppled gravy jug – of a roast dinner.

In the living room, set designers have recreated the scene in which thousands of copies of Harry Potter’s Hogwarts’ acceptance letter fly out of the fireplace. As on other sets, information panels (in Japanese and English) explain how key scenes were created.

While filming this scene, for example, pressurised air blew the 10,000 letters into the Dursley’s home.

Producing 10,000 letters takes time, and – unlike Harry – designers couldn’t simply conjure up spares. But the sheer number of duplicates required for filming meant there was no shortage of props for the Tokyo tour.

Some of the 3,000 wands created for the films are here, too, as is Harry’s beloved Nimbus 2000 broomstick.

“One of my favourite stories relates to this machine,” says Roots, of the incredibly detailed coin-operated Eyeball Bonanza machine. “Pierre Bohanna, head prop maker, told me his father made the original for the films, and he recreated this one with his son for Tokyo.”

Elsewhere, I spot the actual guitars strummed by the Weird Sisters in Harry Potter and the Goblet of Fire, and the Weasleys’ grandfather clock. Apparently, before filming, designers hunting for props snapped it up at an antiques auction in England and then added pendulums to ramp up the wizardry.

My favourites among the many original costumes on display include an invisibility cloak worn by Harry, the beautiful formal gown worn by Leta Lestrange in Fantastic Beasts: the Crimes of Grindelwald, and the dress worn by Hermione to the Hogwarts Yule Ball.

The Defence of the Dark Arts set depicts the classroom as used by Professor Remus Lupin. Seven professors taught the subject during the eight films, and each brought their own accessories. Lupin’s room has some fetching vertebrae-shaped candles.

Iconic sets such as Diagon Alley can also be found at the London attraction, but the attention to detail means they’re equally impressive here – one of the most popular spots is the Wizard Wheezes magic shop, where an animatronic boy vomits a constant flow of Puking Pastilles into a barrel.

In a section of the tour dedicated to the non-human actors, I learn that the 250 animals on the filmmakers’ payroll included a hippo and wolves. There are displays of pigment jars used by designers to hand-paint backdrop canvases, some of which were 180 metres (590ft) long.

As with the London attraction, the Tokyo tour ends at an enormous model of Hogwarts, complete with tiny glowing windows, wind-sculpted pine trees and ornate brickwork.

And the fun doesn’t stop once you leave.

The quickest way back to central Tokyo, 15km to the southeast, is by train from the nearby Toshimaen station to Ikebukuro station. Both have been given Harry Potter-themed makeovers and now resemble Hogsmeade station (courtesy of a red telephone box and wrought iron benches) and Kings Cross’ Platform Nine and Three Quarters (which has brick-effect wallpaper and ornate station clocks), respectively.

The makeovers will be in place for a year, as will the wrap on the train that connects the stations and features images of Harry and others.

Arriving at Ikebukuro station, the gaggle of visitors dressed as Harry Potter attract puzzled glances as they disappear into the crowd of stressed commuters, although these wizard-loving Tokyoites, clutching their newly bought wands, are oblivious.

Perhaps we could all be more Harry.