He placed the silk sack on top of the cast-iron frame, immediately above the strings. The sack contained enough Cordite MD smokeless powder to propel a twelve-pound shell two miles.

YAMAMOTO KENTA LEFT the Gun Factory the way he had entered, his eyes still stinging from the ammonia. Suddenly, things went wrong. The North Railroad Gate was blocked by an unexpected burst of late-night activity. Switch engines were huffing gondola cars in and out, attended by a horde of brakemen. He retreated deeper into the arsenal, past the powerhouse, through a maze of roads, buildings, and storage yards. Orienting himself by the powerhouse smokestacks and a pair of experimental radio-antenna towers silhouetted against the moonlit sky, he crossed a park and gardens bordered by handsome brick houses in which slept the families of the commandant and officers of the yard.

The ground rose higher here. To the northwest he glimpsed the Capitol looming over the city. He saw it as yet another symbol of America ’s fearsome might. What other nation could have erected the largest cast-iron dome in the world at the same time they were fighting a bloody Civil War? He was almost to a side gate when a sentry surprised him on a narrow path.

Yamamoto had just enough time to back into a hedgerow.

His capture would disgrace Japan. He was ostensibly in Washington, D.C., to help catalog the recent contribution of the Freer Collection of Asian art to the Smithsonian Institution. The front allowed him to mingle with the Diplomatic Corps and powerful politicians, thanks to their wives who fancied themselves artists and hung on his every word about Japanese art. Genuine experts at the Smithsonian had caught him off base twice already. He had blamed gaps in his hastily learned knowledge on a poor command of English. So far, the experts accepted the excuse. But there would be absolutely no plausible explanation for a Japanese curator of Asian art caught prowling the Washington Navy Yard at night.

The watchman came up the path, boots crunching on gravel. Yamamoto backed in deeper, drawing his pistol as a last resort. A gunshot would rouse Marine guards from their barracks at the main gate. Deeper he pushed, feeling for an opening in the branches that would lead out the other side.

The watchman had no reason to look into the hedgerow as he plodded by. But Yamamoto was still pushing backward against the springy branches, and one snapped. The watchman stopped. He peered in the direction of the sound. In that instant the moon bathed both their faces.

The Japanese spy saw him clearly-a retired sailor, an “old salt,” supplementing his meager pension with a night watchman’s job. His face was leathery, his eyes bleached by years of tropical sunlight, his back stooped. He straightened up at the sight of the slender figure hiding in the hedge. Suddenly galvanized, the pensioner was no longer an old man who should have called for help but was hurled back to his time as a long-limbed, broad-shouldered “blue jacket” in the full tide of life. A strong voice that once carried to the mast tops demanded, “What the devil are you doing in there?”

Yamamoto wormed out the back of the hedge and ran. The watchman pushed into the hedge and got tangled in it and roared like a bull. Yamamoto heard answering shouts in the distance. He changed course and raced along a high wall. It had been raised, he had learned while preparing for his “tour,” after looters invaded when the Potomac River flooded the yard. It was too high to scale.

Boots pounded on gravel. Old men shouted. Electric flashlights flickered. Suddenly he saw salvation, a tree standing near the wall. Digging his india-rubber crepe soles into the bark, he shinnied up the trunk to the lowest branch, climbed two higher, and jumped onto the wall. He heard shouts behind him. The city street below was empty. He jumped down and cushioned a hard landing with flexed knees.

AT BUZZARD POINT, near the foot of 1st Street, Yamamoto boarded an eighteen-foot motorboat powered by a two-horse Pierce “Noiseless.” The pilot steered into the current and down the Potomac River. A shroud of surface mist finally closed around the boat, and Yamamoto exhaled a sigh of relief.

Huddling from the cold in the cubby under the bow, he reflected upon his close call and concluded that his mission had suffered no damage. The garden path where the night watchman had almost caught him was at least a half mile from the Gun Factory. Nor did it matter that the old man had seen his face. Americans were contemptuous of Asians. Few could distinguish between Japanese and Chinese features. Since immigrants from China were far more numerous than those from Japan, the watchman would report an intrusion by a despised Chinese-an opium fiend, he thought with a relieved smile. Or, he chuckled silently, a nefarious white slaver lurking to prey on the commandant’s daughters.

Five miles downriver, he disembarked in Alexandria, Virginia.

He waited for the boat to depart the wooden pier. Then he hurried along the waterfront and entered a dark warehouse that was crammed with obsolete naval gear deep in dust and spiderwebs.

A younger man whom Yamamoto had labeled, scornfully, “The Spy” was waiting for him in a dimly lit back room that served as an office. He was twenty years Yamamoto’s junior and ordinary-looking to the point of being nondescript. His office, too, held the outdated paraphernalia of earlier wars: crossed cutlasses on the walls; a Civil War-era Dahlgren cast-iron, muzzle-loading cannon, which was causing the floor to sag; and an old 24-inch-diameter carbon arc battleship searchlight propped behind his desk. Yamamoto saw his own face mirrored in its dusty eye.

He reported that he had accomplished his mission. Then, while the spy took notes, he related in precise detail everything that he had seen at the Gun Factory. “Much of it,” he said in conclusion, “looks worn out.”

“Hardly a surprise.”

Overworked and underfunded, the Gun Factory had produced everything from ammunition hoists to torpedo tubes to send the Great White Fleet to sea. After the warships sailed, it forwarded train-loads of replacement parts, sights, firing locks, breech plugs, and gun mounts to San Francisco. In another month the fleet would recuperate there from its fourteen-thousand-mile voyage around South America’s Cape Horn and refit at the Mare Island Naval Shipyard to cross the Pacific.

“I would not underestimate them,” Yamamoto retorted gloomily. “Worn-out machines are replaceable.”

“If they have the nerve.”

“From what I saw, they have the nerve. And the imagination. They are merely catching their breath.”

The man behind the desk felt that Yamamoto Kenta was possessed-if not unhinged-by his fear of the American Navy. He had heard this rant before and knew how to change the subject by derailing the Jap with lavish praise.

“I have never doubted your acute powers of observation. But I am awed by the range and breadth of your skills: chemistry, engineering, forgery. In one fell swoop you have impeded the development of American gunnery and sent their Congress a message that the Navy is corrupt.”

He watched Yamamoto preen. Even the most capable operative had his Achilles’ heel. Yamamoto’s was a self-blinding vanity.

“I’ve played this game a long time,” Yamamoto agreed with false modesty.

In fact, thought the man behind the desk, the chemistry for the nitrogen iodide detonator was a simple formula found in The Young Folks Cyclopaedia of Games and Sports. Which was not to take away from Yamamoto’s other skills, nor his broad and deep knowledge of naval warfare.

Having softened him up, he prepared to put the Jap to the test. “Last week aboard the Lusitania,” he said, “I bumped into a British attaché. You know the sort. Thinks of himself as a ‘gentleman spy.’”