Mongke looked at the lamp for a moment.

"The Toluid line," he said. "Through me."

He said it the way he said everything in this room, flat and declarative, a statement of what should be rather than an expression of wanting.

Batu received it as what it was and moved.

"I can deliver the Jochid plurality at whatever kurultai convenes after Ogedei dies," Batu said. "The whole faction and its military might, all of it goes toward your name when that moment arrives."

Mongke turned his cup in his hand without drinking.

"What does the plurality actually constitute," he said. "In votes."

Batu did not hesitate.

"The Jochid line’s full count, plus the minor princes Orda has already moved toward our position. However, that number doesn’t give you the throne alone."

Mongke set the cup down.

"No. I’d need the Toluid line behind it, and I’d need Koden’s abstention at minimum."

He looked at Batu directly.

"All of which I can manage if the Jochid plurality is committed before the succession question. Before."

"Before," Batu said.

Mongke’s gaze was steady.

"And in return."

Batu met it without shifting.

"You want the western territories named as a permanent khanate," Mongke said. "A standing authority carrying its own Chinggisid legitimacy."

Mongke tilted his head slightly, considering the partition.

"And you want the legitimacy to come from whoever holds the eastern throne."

"Will we have a problem with that."

He let the implication be raised before continuing.

"I’m being asked to sanction a reduction in the authority of the position I haven’t yet held."

The tone was not objection. It was the precise volume of probing before making a decision.

"It doesn’t reduce the eastern throne’s authority," Batu said. "It defines the eastern throne’s domain as the east. What you give up is authority over territories you can’t actually govern from the ancestral land anyway."

He shifted slightly, hammering the point.

"A Great Khan in Karakorum cannot govern what happens a year of hard riding to the west. The authority you’re formalizing is one your predecessors have been unable to exercise in practice, regardless of what the formal title says."

Mongke’s mouth moved faintly, not quite a smile.

"That would be more persuasive if I were the one being asked to believe it rather than help sell it to everyone else."

Batu matched his gaze.

"You’re asking me to be the Great Khan of a divided empire," Mongke said.

He let the importance of it sit between them.

"The first man to look at what Genghis conquered and name its eastern half as all he governs. Every traditionalist between here and the eastern sea will use that against my succession before I’ve made a single decision."

Batu answered without hesitation.

"The merchants from the west speak of an empire that stood for centuries after a division like this," he said. "A Persian trader in Bukhara described it to me on the southern route."

He paused, letting the comparison take shape.

"He called it Rome, though by his time only the eastern half remained. A single empire that once expanded from the northern sea to the desert edge, larger than ours by some accounts. When it grew past what one center could manage, it divided."

Batu’s voice stayed even.

"Two emperors, governing their half. The western half fell eventually. The eastern has been standing for many centuries after."

A brief silence.

"The division wasn’t what killed the western half. It was what kept the eastern half alive."

Mongke was quiet.

He was a known man, and had heard of similar tales. The idea wasn’t so absurd when first put on words now.

"For how long you have been planning this?" Mongke said.

"Ever since three assassins sent by Guyuk were killed in my ger."

He watched Batu more closely.

"The western campaign is the key for you success."

His eyes sharpened.

"And the field command is the mechanism. You’re trying to make the western territories permanent before the empire can call you back east."

"Indeed."

Mongke kept the thought a moment longer.

"And while you stay west, you want me to legitimize your position."

Batu did not soften the answer.

"As the Great Khan of the East, yes."

He leaned slightly forward.

"Because what actually exists in the east is still an empire that was never seen before."

A beat.

"And your goal should be to prevent it to collapse, not to burden it further."

Mongke looked down at the table.

He was not convinced. He was thinking again from a different perspective. When he looked up, his gaze had hardened.

"Guyuk will challenge this decision by citing the unified imperial ideal," he said. "Genghis’s stated vision, a single sky over a single people."

His eyes were cold.

"What prevents that challenge from being effective?"

"The Chinggisid blood in both authorities is Genghis’s blood," Batu said. "The sky is the same, and so is the people. The division only happens on the administrative and military sphere."

He did not rush the conclusion.

"And any prince who wants to challenge it needs the combined weight of the Jochid and Toluid standing to fail simultaneously. Even Chagatai and Guyuk are capable to force this outcome."

Mongke’s fingers tapped once against the cup.

"You’re assuming this division remains across successions."

"I’m assuming the division creates conditions under which it is advantageous for successive holders of both positions to maintain it."

Batu’s tone remained precise.

"A western khanate and an eastern Great Khan who support each other carry more combined authority than a unified empire that can’t govern part of it."

Mongke shook his head slightly.

"This type of reason will crumble when personal interest runs the other way. For instance, Ogedei and Chagatai spent years undermining each other while nominally governing under the imperial framework."

"Ogedei and Chagatai have overlapping domains," Batu said. "What I’m describing has a line between them."

He locked Mongke’s gaze.

"When the domains don’t overlap, there’s no reason for conflict."

Mongke sat with that.

The lamp was steady between them. The felt walls kept the Orkhon valley’s night outside, the distant sounds of the camp reduced to almost nothing.

He said nothing.

Mongke was building the larger picture. He would arrive where the success was, or find the flaw.

At last, he looked up.

"I can see how it would work," he said.

He did not soften it.

"The question is whether the division remains amicable when one side can benefit from breaking it."

"Yes," Batu said. "That’s the question."

Neither man spoke.

Batu looked at the table and did not add anything. What had been said was sufficient.

They had agreed.

Mongke stood.

Batu stood with him.

Mongke extended his right forearm, held straight, knuckles turned slightly upward.

Batu placed his right hand under the elbow, full support, palm flat beneath the joint. The gesture, in every steppe tradition he knew, meant I will support you.

They held it for three seconds.

Then Mongke took the cup from the table, his own cup, still with airag in it, and held it toward Batu.

Batu took it, drank, and handed it back.

Mongke drank from the same cup, and set it down.

Neither man spoke.

Batu turned and stepped out into the night air.

Suuqai stood at the ger’s edge, watching the approaches. He fell in position without instruction.

The Toluid camp stretched around them. The northern margin lay ahead, toward the Jochid lights.

The Orkhon ran somewhere to the east, audible in the dark.

The stars above it were clear and enormous.

Batu walked north through the camp and did not look back.