Page 13 of Daikon

He began to walk slowly around the object, moving away from the nose, tapping the casing here and there as he went.

There was evidence of where several protuberances had extended from the black steel shell.

They were now broken off or smashed flat, their original purpose unclear.

A hoisting shackle was the only thing Kan recognized.

Its location, well forward, indicated that the object was nose heavy.

He paused at a figure, L10, painted in large white characters on the left side. Some sort of identifier? Was this the tenth unit in a series?

He turned his attention to the handwritten inscriptions that PO Yagi had mentioned on the walk down.

Some were still legible, not scoured off in the crash.

Samuel Filson, USN… Edward Houseman, for Charlie …

For the boys on Hancock Street, Detroit USA…

Sgt. Ralph T. Hickey… To Emperor Hirohito, Special Delivery to where the sun don’t shine.

He paused to consider this last inscription. It was the sort of thing, he realized with a chilling sensation, that an American would write on a powerful weapon before sending it to Japan.

“Can you read English?” asked Yagi.

“A little.” Kan in fact knew English very well. He had done his doctoral work in physics in the United States, at the University of California in Berkeley. It was there that he had met his American-born wife Noriko, an English major, in 1936.

He continued along the casing, moving toward the tail, reading more inscriptions, mostly names.

A twisted, flattened mass of metal lay on the floor at the rear of the object, some sort of stabilizing tail fin structure that had been cut away.

An open cavity was exposed underneath, the end of a tube extending into the object.

It was roughly the diameter of Kan’s hand, fingers outstretched.

The heavy steel plug lying on the trolley presumably screwed into the end.

“Yagi-heisō,” he said. “You mentioned removing an explosive charge from the back.”

The petty officer casually retrieved four tubular bags from the workbench. They drooped in his hands like fat, stubby worms as he showed them to Kan.

“Cordite,” he said. “Total four kilos. About a meter inside after I unscrewed that steel plug. These wires were attached to the cordite. These points…” Yagi indicated the pencil-sized rods protruding from the end of the plug. “I figure they must be primers.”

Kan examined the cordite and primers. More evidence. That was not good.

He moved around to the far side of the object. More inscriptions here: F. A. Scudder … Lt. Howard Roach… Here’s a hot one for you, Tojo … Stanley J. Rothstein—

The name stopped Keizo Kan cold. He had known a Stanley J.

Rothstein at the University of California.

Everyone called him Stan or SJ. A fellow doctoral student in the Department of Physics, quite brilliant.

Could this be the same man? Had Stan been recruited into the same type of war work?

No, surely not. The population of the United States was more than one hundred million.

There had to be more than one Stanley J. Rothstein in the United States.

Kan continued with his examination, a troubled look now clouding his face.

Working his way back to the nose, he confirmed that it was solid by tapping with his knuckles.

Unlike the rear two-thirds of the object, which rang hollow and was evidently bomb casing, the forward third appeared to be machined from a solid steel block.

The scoring lines where it had been cut were clearly apparent.

The forward cavity was much larger than the hole in the tail.

Kan bent down and peered in, using the flashlight that Yagi provided.

The outermost portion, machined steel, shone like a mirror in the light, the space large enough to accommodate his whole head if he cared to insert it, which he did not.

Then it narrowed to less than half the width—the same width as the tube opening in the tail.

The tube evidently extended down the entire length of the object.

Its first sixty centimeters here in the nose, not quite the length of Kan’s arm, was some sort of collar or sleeve of a dark material—coarse grained, very hard, flecked with green.

Sintered tungsten carbide, perhaps? Beyond this, the interior gleamed like the outermost portion of the cavity. Machined steel again.

No actual design for an atomic bomb had been produced in Project Ni-Go, but the basic form such a weapon would take had inevitably come up in discussions.

Kan and his colleagues understood that it would be a gun-type design, one in which a uranium-235 projectile was fired into a U-235 target to form a supercritical mass.

Such a weapon would have at its heart a cylinder of machined steel, a gun barrel, to facilitate the firing—a cylinder like what he was gazing at now.

Kan looked down at the nose assembly, hidden under a piece of canvas. He used his toe to gingerly lift the edge of the fabric.

Stanley J. Rothstein…

Yagi stepped forward and pulled back the canvas.

“Screws in like the plug in the tail,” he said. “A real heavy bastard.”

The assembly consisted of a stack of four distinct components, each progressively smaller, held together on a thick rod.

Kan’s eyes immediately went to the small end—the innermost end when the assembly was inserted into the cavity in the nose.

There were six rings here, covered on the outside only with a bright silvery plating.

The rings themselves were of a gray metal with a plum-colored patina.

He had never seen anything quite like it before.

“This is how it appeared when you removed it?”

“Yes,” replied Yagi. “I put the outer pieces back on the rod after we did the testing. Uranium, that’s what we figured. That plating—I don’t know what it is.”

Kan gazed down at the plum-colored rings. They were of the same diameter but varied in thickness, suggesting that they had been individually cast.

“Conducting a specific gravity test was very resourceful,” he said. “Were you a teacher before entering the Navy?”

“A teacher!” One side of Yagi’s mouth curled up in amusement and he made a dismissive snort. “I was a mechanic. In my father’s garage in Osaka. Yagi Shokai.”

Kan cast Yagi a glance, wondering if he had inadvertently offended the man. The petty officer met his eyes with a look of defiance.

“So you know cars,” said Kan.

Yagi made a single nod. “Cars and trucks.”

Kan squatted at the nose assembly, his knees popping like an old man’s.

He unscrewed the large nut from the end of the rod, removed the outermost ring and hefted it in his hand.

It was extremely heavy, possibly four kilos, yet no bigger than the donuts he had enjoyed in the cafeteria at the University of California—a bit flatter, slightly bigger around.

Although one of Japan’s foremost uranium experts, he had never seen anything like it.

His experience had been confined to handling uranium hexafluoride, which in solid form looked like white, crystalline rock salt, and to a lesser extent uranium oxide, a coarse yellow powder processed from uranium ore.

He opened the wooden case he had brought with him.

“Geiger-Müller counter,” he said in response to Yagi’s questioning look.

The counter was an old and familiar piece of equipment from happier days—and precious, with almost everything at the Riken now destroyed.

It had accompanied Kan and his colleagues to Gunma Prefecture in 1938, on an expedition to collect cosmic ray data from inside Shimizu Tunnel, deep underground.

And then there was the time Noriko had visited the laboratory with Aiko, a lifetime ago in 1942.

Kan had taken time from his busy schedule to have some fun with his daughter, showing her this very counter, demonstrating how the rate of the clicking it made increased when he placed the Geiger-Müller tube in the wand near a glass of water containing a sodium isotope, which was radioactive.

“Now close your eyes,” he had instructed. Aiko’s eyes closed. He gulped down the water.

“The water is gone!” he exclaimed when Aiko opened her eyes and saw that the glass was empty. He led her on a search about the lab with the counter, checking under desks, in the corners, behind stacks of books and papers, muttering all the while, “Now where did that water go?”

Finally he passed the wand near his stomach, making the counter erupt with a flurry of clicks.

“It’s in your stomach,” Aiko had said, her eyes wide.

“In my stomach? Oh yes, of course. I drank it!”

He gave the wand to Aiko to pass over his belly. And Kan and his wife and his daughter had laughed.

The rings of plum-colored metal sparked a much more vigorous response than the water he had drunk.

As Kan brought the Geiger-Müller tube in close, the sporadic clicks of background radiation increased to a flurry and merged into a harsh buzz, the needle on the gauge climbing past 200,000 counts per minute.

It subsided when he moved the wand down the nose assembly, down past the tungsten carbide disk, then the outer steel pieces.

He returned the wand to the rings. The counter began buzzing again.

Gamma radiation. The reading was high but in line with what would be expected. Coupled with Yagi’s specific gravity test, the conclusion was clear.

Kan let it sink in. He started nodding his head.

“I think you’re right, Yagi-heisō,” he said. “This could be uran .”

He would need to conduct his own testing, but he accepted it now. His mind leaped ahead instead to the next question: Had the U-235 content in these metal rings been significantly concentrated? As fantastic as it seems, could this uranium really be enriched?