Edo Castle dominated its wooded hilltop, a great fortified city-within-a-city that housed the shogun Tokugawa Tsunayoshi, his family, his closest allies, and a veritable army of soldiers, officials, and servants within its massive stone walls.

Sano walked up to the shimmering moat, gazing at the castle with the awe that this symbol of Tokugawa supremacy always inspired in him. For the first time, he grasped the full extent of Lord Niu’s madness. Who in his right mind would dare challenge this? The castle had stood for almost a hundred years, and it looked ready to stand for at least as many more, judging from the strength of its defenses. Countless samurai stood inside guardhouses that topped the walls, and more occupied lookout towers. Above the walls, the keep soared five stories high, a square white tower composed of many smaller towers. Its gables and barred windows provided lines of fire to archers and gunners; its plastered walls and tile roofs could resist both fire arrows and bullets. At ground level, a battalion of guards manned the iron-plated main gate. Armed with muskets as well as swords, they controlled the heavy flow of traffic in and out of the castle.

Watching the visitors, mostly samurai who presumably had legitimate business inside, Sano felt more than a little intimidated. He’d never been inside the castle; his family was too unimportant and his rank too low for him to have enjoyed the honor. But he knew that somewhere, deep inside the palace, were the headquarters of the Tokugawa spy network. There the metsuke collated and interpreted information gathered by agents and informers all over the country and distributed it to the shogun and his advisers. To them he must bring the news of the treasonous Conspiracy of Twenty-One.

Still he hesitated, reluctant to cross the bridge. Except for Cherry Eater’s word, he had no evidence that the conspiracy planned to kill the shogun. He didn’t know how, when, or where the assassination attempt would take place. His own conviction that the plot gave Lord Niu a motive for the murders wouldn’t influence the authorities. After all, Raiden had been executed for Yukiko’s and Noriyoshi’s murders, and Tsunehiko’s death officially ruled a highway killing. He would just have to tell his story from the beginning, present his conclusions, and hope that the metsuke would draw similar ones. Taking a deep breath, he squared his shoulders and marched across the bridge.

“I would like an audience with the metsuke ,” he told the guards, after identifying himself.

They looked him over in a bored fashion. One of them said, “Show me your pass.”

“I don’t have one. But I’ve come on a matter of extreme urgency.” Sano had anticipated difficulty in getting past the castle’s security, which protected its occupants not only from physical threats but also from callers who might waste their time. “I bring news of vital importance to the shogun,” he added. “Please allow me to convey it to the metsuke .”

“ ‘Vital importance, ’ eh?” The spokesman leaned on his spear. “Suppose you tell me what it is. I’ll see that it gets to the right people.”

Imagining how his story would be distorted as it passed through the castle’s bureaucratic channels-possibly never reaching the metsuke at all-Sano shook his head. “I must speak with them personally.”

“Well, you can’t.” The guard shed his veneer of courtesy, his voice turning sharp. He was a Tokugawa foot soldier, one of a breed known for their arrogance and rudeness. “Either leave a message, and if the metsuke want to see you, they’ll send a summons. Or else get lost. We’re busy.” He turned to question an arriving party of samurai.

Sano had managed to extract one more piece of information from Cherry Eater before freeing the drenched and indignant shunga dealer: the identity of the metsuke to whom Noriyoshi had reported. But Cherry Eater wasn’t sure whether the exact name was Jodo Ikkyu or Toda Ikkyu.

Taking a chance, he said, “Toda Ikkyu will have your heads if you don’t bring me to him at once.”

The guard’s head snapped around. “You’re Toda’s creature?” His face relaxed from a scowl to a knowing smirk. “Why didn’t you say so in the first place?” Banging on the gate with his spear, he shouted to someone inside. Another guard came out. “Take this man to Toda Ikkyu.”

The other guard gestured for Sano to follow him. Sano realized that they thought he was one of Toda’s informers. Well, he was, in a way. And he’d learned that this was how the government bureaucracy worked: by manipulation of men through their fear of their superiors.

Inside the gate, more walls formed a square enclosure designed as a trap for invading enemies who managed to penetrate the castle’s outer defense. At least twenty more guards stood watch, rigid and stern. They took away Sano’s swords and searched him for hidden weapons. Then they swung open another gate that stood at right angles to the first.

This opened into a large courtyard bordered by long wooden sheds hung with red curtains. Inside them, Sano could see row upon row of weapons: swords, bows, spears, muskets. Hundreds of armored samurai stood in or in front of the sheds. Others, mounted on horses caparisoned with battle regalia, paced the courtyard. The odor of horses sharpened the air; the tramp of restless feet and the rumble of voices echoed off the walls. Beyond a second moat and bridge stood another wall. The keep towered above it, looking grimmer and more solid than from a distance. Sano felt tiny and insignificant in the presence of such military might. Lord Niu’s madness must give him superhuman courage.

Once past another set of sentries and across the bridge, Sano entered another enclosure, with more guards and yet another gate. This gate led to a narrow, gradually ascending passageway full of turns and angles. Gun holes and arrow slits pierced the white plaster walls of enclosed corridors that ran along the high stone walls. At regular intervals, larger square openings in the corridors allowed the defenders to dump stones on anyone who tried to climb the walls. Sano spied more guards behind the openings. The other visitors he saw all had their own military escorts. Only samurai wearing the Tokugawa crest walked proudly alone and armed. Sano soon lost count of the number of checkpoints and gates he passed. Tokugawa Ieyasu had built his fortress to withstand a siege, but were his descendants safe from treachery? Remembering the fanatical gleam in Lord Niu’s eyes, Sano wondered. Perhaps the Conspiracy of Twenty-One planned to somehow ambush the shogun outside the castle walls, away from his legions of soldiers.

The final gate brought them at last to the castle’s inner precinct. There bands of guards patrolled a formal garden landscaped with plane trees, pines, and boulders. A wide gravel path led to the palace.

Sano stopped involuntarily to take in this sight he’d never expected to see. The low, vast palace had white plaster walls with dark cypress beams, shutters, and doors. Its heavy dark tile roof peaked in many high and low gables, each crowned with a gilt dragon. Serene and elegant, it drowsed in an oasis of tranquillity, far removed from the teeming streets of Edo. Only the faint strains of music and the muffled report of firecrackers disturbed its peace:

Setsubun celebrations were going on within its walls and courtyards, or in daimyo mansions elsewhere on the castle grounds. Sano thought of Lord Niu’s speech. He reflected that the Niu and other daimyo clans had indeed purchased a fine home for the Tokugawas.

The guard interrupted Sano’s thoughts. “Hurry up,” he ordered.

They crossed the garden and gained admittance from the guards at the palace’s carved door. As he removed his shoes in the spacious, echoing entry hall, Sano marveled that he should visit the castle at all, let alone for such a purpose.

Inside the palace, a labyrinth of corridors unwound before Sano, angling their way through the outer portion of the building, which served as government offices. Sunlight from the barred windows fell in bright lines across polished cypress floors. Wide halls led past airy reception rooms with daises, coffered ceilings, and lavish landscape murals. The narrower ones were lined with small chambers. There a few doors stood open to reveal an official dictating to his secretary, or a meeting in session. Twice Sano’s escort saluted pairs of patrolling guards; once they both bowed to an official in flowing robes. Otherwise the palace seemed virtually deserted. An unnatural quiet pervaded the great complex that must normally buzz with the sound of officialdom in motion. The creak of the floor beneath their feet echoed through the empty corridors. Other soft creaks came infrequently from deeper within the building. Already quivering inside with tension, Sano started at each one.

“Setsubun ,” the guard grumbled. “Those office layabouts have all quit for the holiday already.”

He led the way down a very narrow, dim passage and through the only open door in it. Inside, paper-and-wood screens divided a long, thin room into many small compartments, each with its own window. As Sano passed each one, he saw desks and shelves stacked with books, scrolls, message containers, and writing implements. Maps hung on the walls, some stuck with colored pins. So this was the castle’s intelligence center. A heavy odor of tobacco smoke underlay the scent of the herbs used to freshen the room for New Year. But the metsuke whose pipes had permanently tainted the woodwork were not here now. The room was cold and silent and dim, with most of the windows shuttered. No lamps burned, save in the very last compartment.

There a man dressed in black stood before a wall of shelves. At the sound of their footsteps, he paused in the act of straightening a row of books and turned.

“What is it?” he asked the guard. “Who is this man?”

“One of your informers, Toda-san ,” the guard answered, looking surprised.

Sano gazed with curiosity at Toda Ikkyu, the first metsuke he’d ever encountered. Seldom had he seen anyone so nondescript. Toda was neither tall nor short, fat nor thin. Of indeterminate age, he had thick black hair that might have given him a youthful appearance, if not for the weary expression in his eyes. His regular features, without particular flaws or beauty, could have belonged to any of a thousand men. Although Sano studied Toda’s face carefully, he doubted whether he would remember it when he left. Perhaps this utter lack of distinction was an advantage for someone in Toda’s profession.