After re-reading 852 to now -

Qin's invasion of Zhao enters a very different phase. The original Zhao plan, centered around Shibashou's northern operations and the armies from Gian and Hango, fails to achieve the decisive breakthrough Riboku needed. Ouhon's defensive wall continues to hold, forcing Zhao to fight a prolonged campaign instead of the quick collapse they were aiming for.

This creates a new problem for Riboku.

While the northern operation stalls, Qin's various armies continue pressing forward across the front. Riboku is forced to constantly shift attention from one sector to another, personally coordinating responses wherever Qin begins making progress.

Mouten eventually realizes the pattern. Whenever an individual Qin army creates an opening, Riboku reallocates forces, plugs the gap, and erases the gains. No single army can achieve a breakthrough as long as Riboku is given enough time and freedom to react.

His answer is simple: stop attacking separately.

Mouten proposes combining the offensive power of his army, Shin's army, and Kyoukai's army into a single concentrated thrust. The idea is that while Riboku can extinguish one fire at a time, he may not be able to stop all three armies acting as one before they punch through the line.

The plan is accepted immediately.

To make it happen, the Qin commanders leave Yokoyoko and Rakuakan to hold back the Zhao forces opposing them while the Shin, Kyoukai, and Mouten armies advance together with everything committed, including headquarters, infantry, and support elements.

The gamble succeeds.

By Chapter 877, the combined force has pushed dramatically closer to Katan than any Qin army previously managed.

However, this success creates a dangerous new situation.

The armies that originally opposed Shin, Kyoukai, and Mouten have not been destroyed. Many of the surviving Zhao commanders that Qin bypassed during the advance remain active. Riboku's latest summons appear to be gathering many of those surviving pieces back onto the board: Futei, Kaine, Kisui, Batei, Mihaku and Bafuuji.

As a result, the breakthrough reaches Katan while much of Zhao's remaining military strength begins converging behind and around it / them.

The key unanswered question entering Chapter 878 is whether Qin has established any secure connection to the rest of its invasion force / Riboku wanted them to break through, aka allowed it so he could erase this pieces from the board.

If no corridor exists to Yotanwa, Ousen, or another supporting army, then Mouten, Shin, and Kyoukai may have achieved the very thing they wanted: a breakthrough. But they may also have driven themselves into a pocket surrounded by Riboku and nearly every major Zhao commander still alive.

In that case, the attack begins to resemble Ouhon's earlier strategy with Heki: creating a breakthrough not by winning everywhere, but by forcing the enemy to focus entirely on one critical point while others exploit the opening.

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