Rainy season

The rainy season is more than a seasonal backdrop: it shapes when armies can move and turns weather into part of the struggle for political advantage. Toranaga’s forces prepare for a campaign during the rains, while his opponents also contemplate a rainy-season march. The choice exposes the risk shared by both plans: each side must act within a narrow political window, even when the season makes military movement harder.

Seasonal Constraint and Strategic Opportunity

The season’s strategic force is clearest in the contrast between the public timetable and the concealed one. Toranaga tells his commanders that Ishido will attack the Kwanto when the rains cease, but the decision to launch Toranaga’s own attack during the rainy season is withheld from those present. The weather thus becomes both a practical obstacle and a screen for surprise: Toranaga’s plan depends on moving before an enemy expects him to act.

The risks are concrete in Kasigi Omi’s reaction. He anticipates fighting through the rains in the Shinano Mountains and doubts that the northern route can succeed. Toranaga’s confidence rests partly on the claim that his guns will force a way through; Omi, promoted to second-in-command, has no alternative plan to offer, but privately regards the venture as madness. Their opposed judgments show how seasonal hardship bears on command as well as movement: the same campaign that Toranaga treats as an opening looks to Omi like a route toward failure.

Toranaga’s Mobilization

Toranaga assigns distinct tasks as he prepares the force. The Attack Regiment is to embark on the galleys for Yedo within five days, under Toda Buntaro with Kasigi Omi as second-in-command. Lord Yabu is ordered to mobilize Izu and send six thousand men to the frontier passes, guarding against Ikawa Jikkyu cutting the lines of communication by moving south. These orders establish preparations on several fronts while the rainy-season attack remains secret.

The division between visible and concealed timing is consequential. The commanders hear that Ishido will attack after the rains, but Omi understands that Toranaga has kept that afternoon’s decision from them. The season therefore marks not one shared timetable but competing expectations: the public forecast delays the decisive move, while the concealed plan brings it forward.

The Opposing Plan

The rainy season is not an opening available to Toranaga alone. Kiyama calls for his allies to mobilize secretly and to wait for the expected postponement of an Imperial visit. That postponement is to serve as their signal that Toranaga has subverted the Most High; they would then march against the Kwanto during the rains on that same day.

The rival plan makes the season part of a contest over interpretation and timing. Toranaga’s opponents would treat the postponed visit as evidence and a trigger for war, while Toranaga’s own preparations conceal an earlier attack. In both plans, the rains magnify the stakes of acting first: seasonal difficulty threatens the army’s movement, but delay also risks surrendering the political and military initiative.