The legend of the young Hino Kumawakamaru, from the late 14th-century Chronicle of Great Peace (Taiheiki), is often used to represent filial piety. Kumawakamaru's father, Hino Tsuketome, was exiled to the island of Sado after plotting with the Emperor Go-Daigo against the Shogunate. At the age of about twelve, Kumawakamaru traveled to Sado to see his father before his execution, but was himself imprisoned by the lay monk Homma Saburō, who presided over Sado island.  Homma then had Tsuketome executed and his ashes given to Kumawakamaru. Feigning illness, Kumawakamaru was transferred to Homma's residence, where he plotted his revenge.  One night, Kumawakamaru sneaked out unarmed, expecting to kill Homma's son. Instead, he came upon Homma himself, asleep in a different room.  He picked up Homma's sword and kicked his pillow to awaken the monk, thinking, "...to kill a sleeping man is no different than stabbing a corpse". When Homma woke up, Kumawaka stabbed him in the chest and throat, and fled to hide in a bamboo grove.  The guards, seeing small bloodstained footprints, went out in search of him. Faced with a deep moat, Kumawaka climbed onto a bamboo, and weighed down the tip of the plant, allowing him to drop over on the other side.  Kumawakamaru finds shelter with an old monk who offers to take him to the harbor and help him secure safe passage off the island. After the last of many captains refuses to take the boy, the monk chants a prayer to capsize the boat if it did not return to shore. As the waters churned about the vessel, the crew hastily returned to shore and took the boy safely to Echigo Province. 

Also seen translated as Yoshitoshi's Warriors Trembling with Courage, this series consisting of thirty-three prints was another extremely popular series designed by Yoshitoshi, as at least five versions of each print in the series were issued.  The series was originally published by Kobayashi Tetsujirō 小林銕次郎 (Maruya Tetsujirō 丸屋銕次郎) from December 1883 through October 1886, and was also republished by Tsunajima Kamekichi 綱島亀吉(Tsujiokaya Kamekichi 辻岡屋亀吉) in 1886.  The Tsunajima series can generally, but not always, be distinguished by the shape of the signature cartouche, a rectangular cartouche with square corners rather than a rectangular cartouche with rounded corners.  Some sources note that the prints issued by Kobayashi Tetsujirō always have a multi-color title cartouche but, in at least one case, the earlier published print has a simple white title cartouche.  As the publisher's name appears in the left margin of all prints that I've encountered from this series, assuming the left margin is intact, then a simple examination of the publisher's name will tell the tale.

When Yoshitoshi designed this series it was towards the end of his career when he was about forty-four, just before his most famous series One Hundred Aspects of the Moon was issued. "The [Courageous Warriors] compositions depict famous warriors from Japan’s past with an intensity and detailed care that demonstrate Yoshitoshi’s reverence for the role long played by warriors in the formation of Japan."¹  "The subject matter of Yoshitoshi’s courageous warriors is drawn mostly from the history of the late Heian period, in particular, the Genpei wars (1180-85) between the Taira (Heike) and Minamoto (Genji) clans and the Warring States period of the mid-15th to late 16th century."²

¹ website of the Brooklyn Museum https://www.brooklynmuseum.org/opencollection/objects/173661
² Yoshitoshi, Masterpieces from the Ed Freis Collection, Chris Uhlenbeck and Amy Reigle Newland, Hotei Publishing, 2011 p. 116.