They smiled at each other, but it was forced this time. Julia didn’t know whether Belmonte believed her or not. He’d leaned back in his wheelchair and was frowning.

“There was something about the painting that I wanted to tell you.” He stopped and thought a little before going on. “The other day, after you and your chess-playing friend visited me, I was thinking about the Van Huys. Do you remember our discussion about a system being necessary in order to understand another system and that both would need a superior system, and so on indefinitely? And the Borges poem about chess and which god beyond God moves the player who moves the chess pieces? Well, I think there is something of that in this painting. Something that both contains itself and repeats itself, taking you continually back to the starting point. In my opinion, the real key to interpreting The Game of Chess doesn’t follow a straight line, a progression that sets out from one beginning. Instead, this painting seems to go back again and again, as if turned in upon itself. Do you understand what I mean?”

Julia nodded, listening intently to his words. What she’d just heard was a confirmation of her own intuition, but expressed in logical terms and spoken out loud. She remembered the list she had made, amended by Munoz to six levels containing each other, of the eternal return to the starting point, of the paintings within the painting.

“I understand better than you might think,” she said. “It’s as if the painting were accusing itself.”

Belmonte was puzzled.

“Accusing itself? That goes some way beyond my idea.” With a slight lift of his eyebrows, he dismissed her apparently incomprehensible remark. “I was talking about something else.” He pointed to the gramophone. “Listen to Bach.”

“We always do.”

Belmonte gave her a conspiratorial smile.

“I hadn’t planned to be accompanied by Johann Sebastian today, but I decided to evoke him in your honour. It’s the French Suite No. 5, and you’ll notice that this composition consists of two halves, each of which is repeated. The tonic note of the first half is G and it ends in the key of D. All right? Now listen. Just when it seems that the piece has finished in that key, that trickster Bach suddenly makes us jump back to the beginning, with G as tonic again, and then slides back again to D. And, without our knowing quite how, that happens again and again. What do you think?”

“I think it’s fascinating.” Julia was following the musical chords intently. “It’s like a continuous loop. Like those paintings and drawings by Escher, in which a river flows along, then becomes a waterfall and inexplicably goes back to the beginning. Or the staircase that leads nowhere, only back to the start of the staircase itself.”

Belmonte nodded, satisfied.

“Exactly. And it’s possible to play it in many keys.” He looked at the empty rectangle on the wall. “The difficulty, I suppose, is to know where to place oneself in those circles.”

“You’re right. It would take a long time to explain, but there is something of that going on in the painting. Just when it seems the story has ended, it starts again, but goes off in another direction. Or apparently in another direction. Because perhaps we never actually move from the spot we’re in.”

Belmonte shrugged.

“That’s a paradox to be resolved by you and your friend the chess player. I lack the necessary information. As you know, I’m only an amateur. I wasn’t even capable of guessing that the game could be played backwards.” He gave Julia a long look. “Unforgivable of me really, considering what I’ve just said about Bach.”

Julia pondered these new and unexpected interpretations. Threads from a ball of wool, she was thinking. Too many threads for one ball.

“Apart from the police and me, have you had any other visits recently from anyone interested in the painting? Or in chess?”

The old man took a while to reply, as if trying to ascertain what lay behind the question.

“Neither the one nor the other. When my wife was alive, people often came to the house. She was more sociable than me. But since I was widowed I’ve kept in touch with only a few old friends. Esteban Cano, for example. You’re too young to have known him when he was a successful violinist. But he died, two years ago now. The truth is that my small circle of friends has gradually been disappearing.” He gave a resigned smile. “There’s Pepe, a good friend. Pepin Perez Gimenez, retired like me, who still goes to the club and drops by from time to time to have a game of chess with me. But he’s nearly seventy and gets terrible migraines if he plays for more than half an hour. He was a great chess player once. And there’s my niece.”

Julia, who was taking out a cigarette, stopped. When she moved again, she did so very slowly, as if any excited or impatient gesture might cause what she’d just heard to vanish.

“Your niece plays chess?”

“Lola? Yes, very well.” The old man gave an odd smile, as if he regretted that his niece’s virtues did not extend to other areas of her life. “I taught her to play myself, years ago; but she outgrew her teacher.”

Julia was trying to remain calm. She forced herself to light her cigarette calmly and exhaled two slow clouds of smoke before she spoke again. She could feel her heart beating fast.

“What does your niece think about the painting? Did she approve of you selling it?” A shot in the dark.

“She was very much in favour of it. And her husband was even keener.” There was a bitter note in the old man’s voice. “No doubt Alfonso has already worked out on which number of the roulette wheel he’s going to place every last cent he gets from the Van Huys.”

“But he hasn’t got it yet,” Julia pointed out.

The old man held her gaze and a hard light appeared in his pale, liquid eyes, but it was rapidly extinguished.

“In my day,” he said with unexpected good humour and only placid irony in his eyes now, “we used to say you shouldn’t count your chickens before they’re hatched.”

“Has your niece ever mentioned anything mysterious about the painting, about the people in it or the game of chess?”

“Not that I remember. You were the first one to talk about that. For us, it had always been a special painting, but not extraordinary or mysterious.” He looked thoughtfully at the rectangle on the wall-“Everything seemed very obvious.”

“Do you know if, before or at the time when Alfonso introduced you to Menchu Roch, your niece was negotiating with someone else?”

Belmonte frowned. That possibility seemed to displease him greatly.

“I certainly hope not. After all, the painting was mine.” The expression on his face was astute and full of a knowing mischief. “And it still is.”

“Can I ask you one more question, Don Manuel?”

“Of course.”

“Did you ever hear your niece and her husband talk about consulting an art historian?”

“I don’t think so. I don’t recall them doing it, and I think I’d remember something like that.” Suspicion had resurfaced in his eyes. “That was Professor Ortega’s job, wasn’t it? Art history. I hope you’re not trying to insinuate…”

Julia realised she’d gone too far, so she produced one of her best smiles.

“I didn’t necessarily mean Alvaro Ortega, but any art historian. It’s not such an odd idea that your niece might have been curious to know the value of the painting, or to find out its history.”

Belmonte looked at the backs of his freckled hands with a reflective air.

“She never mentioned it. And I think she would have, because we often talked about the Van Huys. Especially when we used to replay the game the people in the painting are playing. We played it forwards, of course. And do you know something? Although White appears to have the advantage, Lola always won with Black.”

She walked aimlessly about in the fog for almost an hour, trying to put her ideas in order. The damp air left droplets of moisture on her face and hair. She passed the Palace Hotel, where the doorman, in top hat and gold-braided uniform, was sheltering beneath the glass canopy, wrapped in a cloak that made him look like someone out of nineteenth-century London, in keeping with the fog. All that was missing, she thought, was a horse-drawn carriage, its lantern dimmed by the grey mist, out of which would step the gaunt figure of Sherlock Holmes, followed by his faithful companion, Watson. Somewhere in the murk the sinister Professor Moriarty would be watching. The Napoleon of crime. The evil genius.