I think chess — actually, a number of things that I learned when I was young — it wasn't so much the chess itself; it was the skills that you were training while you were playing chess. So problem-solving, imagination, creative thinking, strategic thinking, all of these things — if you play chess to a high level, what you're really honing is those meta-skills. And I realized from quite young, that's one of the reasons I liked chess was this is a great practice for me to get good — sort of like a mental gym, if you like — to get really good at those other skills, which you could then translate to all sorts of other subjects like science or business.

The reason I've been able to keep going for so long is because of how much I love my sport. I still haven't lost that drive. I'm still as passionate about my sport today as I was when I first laced up a pair of boxing gloves. I love preparing for battle and getting into that mindset you must reach when you're putting your body through torture in training camp.

Amos and I shared the wonder of together owning a goose that could lay golden eggs – a joint mind that was better than our separate minds. … Some of the greatest joys of our collaboration-and probably much of its success – came from our ability to elaborate each other's nascent thoughts: if I expressed a half-formed idea, I knew that Amos would be there to understand it, probably more clearly than I did, and that if it had merit he would see it. Like most people, I am somewhat cautious about exposing tentative thoughts to others – I must first make sure that they are not idiotic. In the best years of the collaboration, this caution was completely absent.

They win the respect, the deserved trust, of the people they deal with, and there is huge pleasure in life to be obtained from getting deserved trust. And so the way to get it is to deliver what you’d want to buy if the circumstances were reversed.

So why do I talk about the benefits of failure? Simply because failure meant a stripping away of the inessential. I stopped pretending to myself that I was anything other than what I was, and began to direct all my energy into finishing the only work that mattered to me. Had I really succeeded at anything else, I might never have found the determination to succeed in the one arena I believed I truly belonged. I was set free, because my greatest fear had been realised, and I was still alive, and I still had a daughter whom I adored, and I had an old typewriter and a big idea. And so rock bottom became the solid foundation on which I rebuilt my life.

So given a Time Turner, I would tell my 21-year-old self that personal happiness lies in knowing that life is not a check-list of acquisition or achievement. Your qualifications, your CV, are not your life, though you will meet many people of my age and older who confuse the two. Life is difficult, and complicated, and beyond anyone’s total control, and the humility to know that will enable you to survive its vicissitudes.