We took a taxi to the Shinjuku district, the hub of Tokyo nightlife, where I’d read you had to be careful. In the heart of Kabukicho, the red-light district where gaming rooms, hostess bars, restaurants, jazz clubs and meetings of the yakuza – the local mobsters – mingle, it was better not to follow just any person, anywhere. We dived headlong into the bustle, the crowd, the vertical luminous signs with incomprehensible ideograms. After locating – with difficulty – the address on Louis’s list, which was very precise, when it came to Tokyo, we found ourselves in the waiting room of Tomohiro Tomoaki, alias Tomo: the celebrities’ tattoo artist. I had to ask him to ink a part of my body, in order to check off this item on my son’s motley Japanese wish list.

The walls were covered with photos of international stars proudly posing, one with an eagle on their hip, another with a greedy mouth at the top of their pubis (really classy – I won’t reveal who it was, even under torture) . . . and I started to wonder what I’d got myself into. Mum was having fun acting the interviewer, filming me while asking me what it was like to be on the point of getting a penis tattoo on my right cheek – ‘You never know what you’ll end up with, with your level of Japanese.’ Ha, ha, very funny. I’d decided to be restrained and have a plain capital L tattooed on the inside of my left wrist. It would be hidden by my watch most of the time.

I closed my eyes while Tomo was tattooing me and, in the end, I was very pleased with the result. Bearable pain, a discreet and beautiful Japanese-style L. We thanked him with a reverential bow that was probably inappropriate – I don’t think I’ll ever understand the complex codes of Japanese greetings – and emerged into the turmoil of Kabukicho.

After drinking a first umeshu in the Golden Gai district, full of microhouses concealing bars which can only cram in five or six people, we entered an izakaya – a traditional restaurant. We removed our shoes and sat on the floor, kneeling on a tatami. Our adventures had given us an appetite. Next on Louis’s list was an exciting and scary command:

Eat in an izakaya, ask for a menu in Japanese, with no photos, order five random dishes and eat them all!

‘You can count me out, pussycat. After all, you’re the one who must follow Louis’s instructions, not me.’

‘You’ve got a nerve, Mum! If you decide you’re going to be my guest – well, you’re my guest to the end! Come on, let’s both have another umeshu – that’ll perk you up!’

My mother raised her eyes to the heavens, feigning exasperation with a broad smile, and answered in her best accent: ‘Go for the oo-me-shoe . . .’