47 of them gathered on 14 December 1702 and, after donning the armor and taking up the weapons from the cache, they set out on their revenge on that same snowy night. Once at Kira's Edo mansion, they divided into two groups and attacked, with one group entering through the rear of the compound while the rest forced their way through the front, battering the gate down with a mallet. Kira's men, many of whom were killed or wounded, were taken completely by surprise but did put up a spirited resistance (one of the ronin was killed in the attack), though ultimately to no avail: Kira was found in an outhouse and presented to Ôishi, who offered him the chance to commit suicide. When Kira made no reply, Ôishi struck off his head with the same dagger that Asano had used to kill himself with. Kira's head was then put in a bucket and carried to the Sengakuji, where Asano was buried. After Ôishi and the others had given the bloody trophy to the spirit of Asano, they turned themselves in.
The rest of the story can be found here.