“Can’t you tell what caused his death?” Disappointment filled Hirata at the thought of returning to Sano empty-handed.

Dr. Ito suddenly halted near the right side of Ejima’s head. He stooped, his gaze intent. An expression of surprise and heightened interest came over his face.

“What is it?” Hirata said.

“Observe this mark.” Dr. Ito pointed to a hollow in the facial bones between the eye and the ear.

Hirata leaned close. He saw a small, bluish, oval spot, barely visible, on Ejima’s skin. “It looks like a bruise.”

“Correct,” said Dr. Ito. “But it’s not from the injuries at the track. This bruise is more than a day old.”

“Then it must have nothing to do with his death,” Hirata said, feeling let down. “Besides, a little bruise like that never hurt anybody.”

But Dr. Ito ignored Hirata’s words. “Mura-san, please fetch me a magnifying lens.”

The eta went to a cabinet and brought a round, flat piece of glass mounted in a black lacquer frame with a handle. Dr. Ito peered closely through it at the bruise, then gave Hirata a look. Enlarged, the bruise showed an intricate pattern of parallel lines and whorls. Hirata frowned in disbelief.

“It’s a fingerprint,” he said. “Someone must have pressed against Ejima’s skin hard enough to bruise it. But I’ve never seen such fine detail in a bruise. What’s the meaning of this?”

As Dr. Ito contemplated the strange bruise, wonderment shone in his eyes. “In all my thirty years as a physician, I’ve never personally seen this, but the phenomenon is described in the medical texts. It sometimes appears on victims of dim-mak.”

“The touch of death?” Hirata saw his own amazement reflected on his men’s faces. The atmosphere in the room chilled and darkened.

“Yes,” Dr. Ito said. “The ancient martial arts technique of delivering a single tap that is so light that the victim might not even feel it but is nonetheless fatal. It was invented some four centuries ago.”

“The force of the touch determines when death occurs,” Hirata recalled from samurai lore.

“A harder tap kills the victim immediately,” Dr. Ito clarified. “A lighter one can delay his death for as long as two days. He can seem in perfect health, then suddenly drop dead. And there will be no sign of why, except an extremely clear fingerprint where his killer touched him.”

“But dim-mak is so rare,” said Detective Arai. “I’ve never heard of anyone using it-or killed by it-in my lifetime.”

“Neither have I,” said Detective Inoue. “I don’t know of anyone in Edo who’s capable.”

“Remember that anyone who is would not publicize the fact,” Dr. Ito said. “The ancients who developed the art of dim-mak feared that it would be used against them, or for other evil purposes. Hence, they passed down their knowledge to only a few favored, trusted students. The techniques have been a closely guarded secret, kept by a handful of men whose possession of it is known only among themselves.”

“Doesn’t it take an expert martial artist to master the techniques?” Hirata asked.

“More than that,” Dr. Ito said. “The successful practitioner of dim-mak must not only learn to concentrate his mental and spiritual energy and channel it through his hand into his victim; extensive knowledge of anatomy is required to target the vulnerable points on the body. The points are generally the same as those used by physicians during acupuncture. The energy pathways that convey healing impulses through the body can also convey destructive forces.”

He touched the bruise with his gloved hand. “This bruise is located on a junction along a pathway that connects vital organs.” He continued, “The need for anatomical knowledge explains why the practitioners study medicine as well as the mystic martial arts.”

“Do you really think Ejima died of murder by dim-mak?” Hirata said, skeptical though intrigued.

“In the absence of any other symptoms besides the bruise, where the killer’s energy entered the body, it is probable,” Dr. Ito said.

Hirata expelled his breath, awed by the import of Dr. Ito’s finding. “Chamberlain Sano will be interested to hear this.”

“We should not be too hasty to inform him,” Dr. Ito cautioned. “The bruise isn’t definitive proof. If my theory is wrong, it could misdirect Chamberlain Sano’s inquiries. Before I can pronounce the cause of death, it should be confirmed.”

“Very well,” Hirata said. “How do we do that?”

Dr. Ito’s expression turned grave. “I must dissect the head and look inside.”

A serious dilemma faced Hirata. He needed to tell Sano exactly how Ejima had died and establish beyond doubt that the death had resulted from foul play, but mutilating the corpse was a big risk. Hirata and Sano both had enemies who were waiting and watching eagerly for them to make a mistake. Should anyone notice signs of an illegal autopsy on a corpse from a case under their investigation, their enemies might get wind of it. Yet Hirata couldn’t fail in his duty to Sano. Casting about for a solution to his problem, Hirata found one that he thought would work.

“Go ahead,” he told Dr. Ito. “I’ll take the responsibility. But please do as little damage as you can.”

Dr. Ito nodded, then said, “Proceed, Mura-san.”

Mura fetched a razor, a sharp, thin knife, and a steel saw. He trimmed and shaved Ejima’s hair in a narrow band from ear to ear across the back of the scalp, then made a cut that circled the head just above the eyebrows. He peeled back the flesh, exposing the moist, bloody skull, then began sawing the bone. The rasp of the saw grated loud in the silence that fell over his audience. Hirata watched, fascinated and repelled.

In his lifetime he’d seen all kinds of gory spectacles-men’s faces cleaved in half and their bellies slit wide open during swordfights, their heads lopped off by the executioner, blood and innards spilled. Yet this methodical butchery disturbed him. It transformed a human into a piece of meat. It seemed the ultimate disrespect for life. Hirata began to understand why foreign science was outlawed, to protect society and its values, at the cost of advancing knowledge.

Now Mura finished cutting the skull all the way around and through the bone. He took hold of Ejima’s head and worked the top free, as though removing a tight lid from a jar. He inserted the knife blade into the skull and scraped the tissue that held its cap in place. Hirata watched Mura lift off the skullcap. Blood oozed out, red and viscous, thickened with clots. It bathed the grayish, coiled mass of the brain, glistened wetly in the lantern light, and soiled the table.

“Here is our proof,” Dr. Ito said with satisfaction as he pointed to the blood. “When a death-touch is struck, its energy travels along the internal pathway that connects the point of contact to a vital organ. Ejima’s murderer targeted his brain. The touch on his head caused a small rupture to a vessel inside his brain, which gradually leaked blood and enlarged until it burst and killed him.”

“And he had no other injuries that could have caused the bleeding?” Hirata said.

“Correct,” said Dr. Ito. “Dim-mak was the cause of death.”

Hirata nodded, but he felt as much apprehension as relief that they knew how Ejima had died. “We’ll go back to Edo Castle and report the news to Chamberlain Sano,” he told the detectives.

“What about the body?” Inoue said. He glanced at Ejima’s corpse, which lay with its brain exposed, the skullcap beside it on the bloody table.

“It goes with us.” Hirata turned to Dr. Ito. “Please have your assistant put Ejima’s head back together, wrap a bandage around it, clean him up, and dress him.”

This was only the beginning of the effort to cover up the examination.