With his game ideas inspired by all areas of his life, it's now company policy for him not to reveal his hobbies, for fear of letting slip details of future projects by implication. During his brief stay in London, he takes afternoon tea with Nintendo UK, watches the Lion King musical in the West End, and has plans to visit Tate Modern and the Design Museum.
"Next year, maybe or maybe not, my own experiences of coming to London and being interviewed in front of a camera might be reflected in a game we will be selling - who knows!" he quips.
"Sometimes I say that my hobby has been translated into specific games, but it's not such an occurrence all the time. Something subtle I've been doing might be incorporated into my way of doing videogames in one way or the other in the end. Only after I have completed a project have I noticed, 'Okay, that bit was based on my own experience.' All I can tell you about my personal life [now] is we started owning a cat," he adds, erupting into laughter.
Of those projects he has taken a greater direct role in of late, New Super Mario Bros. Wii, understandably, is one. Another, due this spring, is Super Mario Galaxy 2.
Before my first audience with Miyamoto (I interview him on three separate occasions during his visit), I play through the demo of Galaxy 2. It's brilliant. Of course it is. But - a Gordon Ramsay kitchen of cursing later - I discover it's also tough. On the way to our meeting I share a lift with Minegawa, who asks: "Don't you think it's too difficult?" laying bare a nervousness within a company which has focused so hard in recent years on attracting new audiences with inclusive experiences.
Speaking to its creator, I'm convinced Galaxy 2 is in part a deliberate offering to Nintendo's core fans, particularly those who feel part of a jilted generation, cast aside for the Wii wrinklies and DS tweens.
"For novice players it might feel that it's a little bit challenging in the first level," Miyamoto acknowledges. "They might find the difficulty level somewhat higher than they expect. For people who already completed Mario Galaxy 1 I think it's going to be a quite challenging game experience.
"Having said that, we've been putting so much energy into controlling Mario in 3D world and we've been trying to make it as easy as possible, so I hope as many people as possible will try it. Even though it may be quite challenging [for novices], as long as they can get to grips with it it'll be a very enjoyable game and that might pave the way for them to appreciate the future 3D games as well."
Structure, here, is everything. And Super Mario World, which saw its Japanese release in 1990, is Miyamoto's greatest architectural triumph. The world map is crafted with unprecedented elegance and subtlety. Within it lies a game which reveals its secrets only to the creative and committed, first through secret exits and Switch Palaces, then the tantalising twinkle of Star Road and onto, ultimately, the punishing extremes of Special Zone with its climactic multi-screen love-letter to gamers, spelled out in coins: "YOU ARE SUPER PLAYER". And once the 96 th and final exit is discovered, the world itself transforms. It remains his masterpiece.
"Whether it's Super Mario World, Super Mario Galaxy or New Super Mario Bros. Wii, our challenge appears to be always the same," Miyamoto says. "We always have veteran players who've conquered all previous Mario games and also we have the newcomers who might not have played any videogames before.
"We have to provide those two types of player with satisfactory entertainment - how we do that is really challenging. That was the particular challenge with New Super Mario Bros. Wii: how we needed to find tweaks to solve the issue for it to become everyone's game. For Super Mario Galaxy 2 we've been trying to incorporate various tweaks including how veteran players can try to collect any and all the stars in the total map.
"So since working on Super Mario World nothing drastic has changed - the map of Super Mario World was made with these two different types of players in mind."
The challenge of Super Mario Galaxy 2 cannot, however, distract from the asteroid-like impact of Wii and DS on the culture, experience and reach of gaming.