In Japan, a 1703 incident during which 47 samurai spent two years plotting the downfall of their master's killer, has inspired countless retellings as kabuki, cinema, and manga. Mythologised and fictionalised versions of the Ronin's exemplary bushido-friendly actions constitute its own genre: Chushingura. It's durable. It's the Japanese 300. What could possibly go wrong with a $175 million Hollywood rendition?

Quite a lot, as it happens.

Much has been written about this grandiloquent samurai epic’s protracted, troubled production, a process beset with reshoots, reedits, and extensive reworkings. 47 Ronin arrives a year late, plenty of time, it transpires, to smooth down all the edges if edges there ever were.

One almost wishes it was the mega-turkey that its convoluted history darkly hints at. But it’s worse and better than that: it’s tasteful, dull, vacuous cinema. The neural hardwiring that insists we love Keanu Reeves playing Zen-like and doe-eyed at the centre of spectacular action ought to offset the tedium. If only 47 Ronin, a grandiloquent samurai epic, had a scrap of spectacular action to recommend it.

There is, to be fair, plenty to look at: between John Mathieson’s crisp cinematography and Penny Rose’s lux kimonos, woodblock pretty cherry blossoms, seriously cool armour, and neat manga-fied beasts fill out every lovely tableau. The presentation is lush: the 3D is deep, impressive and of the same technical calibre as Gravity and Hugo in that format.

One question. When are we getting to the 47 Ronin? We get Keanu playing a mysterious, demon, half-breed who wants to be accepted by the other samurai boys. We get a drippy, doomed romance. We get witches and giants and other unnecessarily supernatural creatures. But we wanted more swordplay. We wanted characters that don’t require a narrator to explain who they are. We wanted lofty pontification about bushido