MONDAY - On an early flight to Tokyo for the biennial motor show, but first to take up an enticing offer from Nissan to try one of its autonomous driving prototypes. This boiled down to accompanying a test driver in a self-driving Leaf on a lightly trafficked 20-minute route across Tokyo Bay via a newly built bridge. It was highly instructive.

I didn’t drive the car – no one did, although it was Nissan’s engineer behind the wheel at all times. Several hacks returned from the experience pronouncing it “amazing”, but that seemed entirely the wrong description. The point was that it felt eerily normal, like going for a spin with a capable but disciplined and pedantic older driver who obeyed every speed limit to the letter and was never tempted to ‘take a line’ through a corner.

Nissan engineers see three levels of hands-off autonomy, but only the third (which they will offer from 2020) requires less than the driver’s full attention to the road. I can seea clear case for the first two levels, but I’m doubtful that our legal system could cope with a driver abandoning responsibility for control of his car to the machine itself.

I haven’t cared much about autonomous driving in the past, but on this evidence it has a big place in our future. It suffers, however, from having a boring name. If it were called Turbo-Steer or Hyper-Drive, we’d take more notice.

WEDNESDAY AM - Mazda’s amazing early-doors reveal of its RX-Vision, a superb new rotary sports car, reminded me of Porsche’s king-hit at Geneva five years ago with its 918 Spyder, whose opening press day launch was so huge that it seemed nothing else would be able match it. Nothing did. Luckily in Tokyo there were half a dozen models of similar significance.

I especially liked Nissan’s IDS Concept, the so-called ‘new Leaf’, and of course Yamaha’s Sports Ride, fully engineered in Guildford by Gordon Murray. It was a vintage show, especially impressive because everything important seemed to be feasible and fully engineered. Part of our job is to provide oxygen to promising unfinished projects, but it’s special fun if you’re convinced the new car can work.     

WEDNESDAY PM - Mesmerising speech by Renault-Nissan CEO Carlos Ghosn, as he explained the alliance’s approach to this motor show’s favourite subjects: electrification and self-driving cars. No doubt Ghosn has great speech writers, but his clarity and emphasis make listening to him a privilege.