The tailagha had been the previous evening. The fire, Buqa’s voice, the entire army under the open sky.

When Batu reached the horse lines the army was already formed on the ground north of Sarai, dressed in the low spring dark before the sun had cleared the east. The spring air had a different atmosphere than the autumn cold of the raid departure. It carried the moisture of thawed ground and new grass coming in beneath the old.

Daichin was saddled at the near end of the personal string. The animal stood with unhurried patience. Batu mounted from the left and rode to the rise.

He stopped there and let his eyes move across what had been put together.

Near forty thousand riders. The autumn had been near thirty-six thousand.

The increase was visible in Toqa-Timur’s contingent at the south, which had grown over the winter from the Suvar spoils, horses and equipment and riders recruited from the tributary clans that submitted through the cold months. His command was the largest among the minor brothers’ contingents and occupied the space accordingly.

Torghul’s tumen was at the head, near ten thousand effective. The relay riders were at their positions not only inside the tumen’s depth but between formations, the signal system running between the nearly four tumens rather than inside each one alone.

The relay had been internal to Torghul’s force through the western steppe campaigns, and now the winter had extended it past those limits. What the spring had inherited was something the autumn raid had not possessed.

Chaidu’s mingan had the forward position in Torghul’s leading section. Kirsa’s mingan was behind it. Both dressed and ready.

Near Torghul’s assault force, slightly apart from the riders around them, Wei’s assistant and a second man held the leads of the pack horses carrying the projector components, the nozzle frame and reservoir were loaded and covered against the spring damp.

Wei himself had stayed at Sarai for the cannon’s second casting, his assistant was the projector’s operator in the field. The equipment and the man were part of Torghul’s assault force now.

Dorbei’s tumen had the center, near ten thousand effective. His riders had the attention of a force that knew the territory they were riding into.

Orda’s White Horde was behind Dorbei, also near ten thousand effective. The relay riders at the junction between his formation and Dorbei’s kept the same timing as the junction between Dorbei’s and Torghul’s.

The beat-slow problem from the early winter exercises had gone, the White Horde assimilated the same doctrine at the same timing as the rest of the Jochid army.

The brothers’ contingents were distributed across the southern half of the column. Tangqut at his position. Toqa-Timur with his expanded section behind him. Berke at the east.

Subutai and his staff occupied the position near the column’s center they had since the Sarai council, outside any tumen’s command structure, from where the full formation was readable. His eyes were already on the ground north of the camp.

The engineer corps was not in the column. Zhao’s eleven men had moved with the vanguard days before the main body formed at Sarai, to set up a bridge at the ford.

The Khar Kheshig had their positions around Batu’s rise, Suuqai at the near side.

The steppe riders at their flanking distances, Gunnar with the horn at his hip. Einar a full head above the riders around him, already facing north. The guard was still building toward a thousand, yet it was already a sizable force.

Torghul raised his arm.

The relay went out across the full formation simultaneously. All three tumens and separate contingents received the signal together, the movement producing a response that spread east and west along the column’s full breadth.

The army moved.

The percussion of forty thousand horses came through the earth before it came through the air. It built as the column’s depth cleared the flat ground north of Sarai and kept building, the sound running ahead of the march across the spring steppe.

The tributary clan pastures ran north for two days, ground the census riders had worked and the raid column had passed in the autumn.

Then the outer reaches, the territory between the last submitted headman and the Upper Volga, which the winter had left open. Orda’s supply depots were what they had always been, reliable ground with good water access, and each evening the army camped without fumbling for it.

The march continued.

By the time the terrain changed, the army had its pace. The soil darkened with moisture as the confluence region drew near. The first reed growth appeared on the eastern drainage rivers, and the horses’ ears adjusted to the smell of standing water and spring vegetation.

The ford came up in the late afternoon.

The reeds stood along the west bank in dense line, but the crossing was different.

Zhao’s bridge spanned the ford in the open afternoon light, timber pontoon sections on float supports, guide ropes fixed to both banks, the surface wide enough to carry horses in files of three. The engineer corps had built it and crossed to the far side before the main body reached the confluence region.

Bayan’s riders were visible on the far bank, they had gone out with the vanguard days before the army formed at Sarai. The far bank had been screened and confirmed clear.

The bridge sat in open daylight, because the army had not come to conceal itself. The Bulgars had known since the raid and plunder during autumn that this day would come.

The vanguard riders spread across the open ground of the far bank in their positions, the screen covering the north and east approaches.

Dorbei’s tumen moved to the bridge.

It crossed at the pace the bridge permitted, section by section in the order the formation had since Sarai. His riders came off the far bank and spread northeast, moving toward the forest where the Bulgar cavalry was sheltered.

The eastern operation was beginning.

Orda’s White Horde followed without pause. His wing had a different heading, north toward the Kama routes, the blocking position that would seal the way out before Bulgar was pressed. He crossed with unhurried certainty.

Both tumens were on the far bank. They spread in their separate directions, Dorbei’s force northeast, Orda’s north, both of them increasing the distance from the bridge and from each other as the assignments given at the war council before became the ground’s reality. Behind them, the Jochid army kept coming.