The shogun seeks to establish a powerful and stable regime under the rule of his own clan; only the Toyotomi, led by the late Hideyoshi’s son Hideyori and based at Osaka, remain as an obstacle to this goal.

The Toyotomi clan in 1614 rebuilds Osaka Castle, which Hideyori as a minor daimyo while his mother Yodo plots a Toyotomi return to power.

At the same time, the head of the clan sponsors the rebuilding of Hōkō-ji in Kyoto.

These temple renovations include the casting a great bronze bell, with an inscription that reads "May the state be peaceful and prosperous; In the East it greets the pale moon, and in the West bids farewell to the setting sun.".

The shogunate, which has its power base in the eastern provinces, interprets this as an insult, and tensions begin to grow between the Tokugawa and the Toyotomi clan, which only increase when Hideyori begins to gather a force of ronin and enemies of the shogunate in Osaka.

Ieyasu, despite having passed the title of Shogun on to his son in 1605, nevertheless maintains significant influence, and by November decides not to let this force grow any larger, leading one hundred and sixty-four thousand men to Osaka (the count does not include the troops of Shimazu Tadatsune, an ally of the Toyotomi cause who nevertheless does not send troops to Osaka).

The siege begins on November 19, when Ieyasu leads three thousand men across the Kizu River, destroying the fort there.

He attacks the village of Imafuku a week later with fifteen hundred men, against a defending force of six hundred.

With the aid of a squad wielding arquebuses, the shogunal forces claim another victory.

Several more small forts and villages are attacked before the siege on Osaka Castle itself begins on December 4.