After two hours, Holmes directed Hammett to an upstairs bed for a rest while he and Russell strolled down to the Italian café, bringing back an assortment of food. Dr Ming plucked curiously at a plate of noodles with a pair of chop-sticks he pulled from his case, but seemed unimpressed with what the Italians had done with the product. Another hour after that, and Dr Ming was on his third pot of tea (“Quite a three-pot problem,” Russell had murmured to Holmes), frowning slightly with the intensity of his excitement, and giving tiny nods of the head from time to time.

Finally, four and a half hours after he had begun, he raised his head to Holmes and said, “Yes.”

“You know where it is?”

But he would answer the question in his own way. “When my friend here explained your problem, it was of interest to me, this matter of anticipating how another man might read the energies. Of course, it simplified matters considerably when I found that the woman whose garden this was left the country shortly after the item was buried. Therefore I could assume that the considerable changes made between her drawing of 1906 and her subsequent one of 1912 would reflect entirely the work of Mr Long Kwo. You see where he has extended the pond a few feet here, and planted a red-flowering bush there?

“You no doubt wonder at this superstition,” he said, carefully not looking at Hammett, who had been sprawling back in his chair for several minutes, as if to put as much distance as possible between himself and this nonsense. “It seems to the Western mind absurd to believe that the manipulation of material objects can change the nature of human emotions, expectations, and perceptions. Yet a room with walls the colour of a peach will make a person feel entirely differently from an identical room whose walls are pale blue. That is a minor example of the precepts of feng shui. In a painting, a small brush-stroke, a specific shape and colour placed in a key position, can change the balance of the whole; in life, a small adjustment in precisely the right place and time may have more effect than an enormous effort elsewhere and later. We use a, hm, mythological language to speak of these adjustments and effects, but that does not mean we believe that there are actual dragons living under the earth.”

Under the force of those sparkling eyes and sensible words, even Hammett had to withdraw his scepticism. He pulled back his outstretched legs and sat nearer upright in his chair, and Dr Ming went back to his notes.