, also known as Matsudaira Keiei, or better known as Matsudaira Shungaku (æ¥嶽) was a Japanese daimyà  of the Edo period. He was head of Fukui Domain in Echizen Province. He is counted as one of the , along with Date Munenari, Yamauchi Yà Âdà  and Shimazu Nariakira. "Yoshinaga" is his imina and "Shungaku" (æ¥嶽, "Spring Mountain") is his gà Â.
Yoshinaga was born in Edo Castle as the eighth son of Tokugawa Narimasa, head of the Tayasu-Tokugawa, one of the gosankyà  cadet branches of the Tokugawa clan. His childhood name was "Kinnojo" (é¦ä¹Âä¸Â). Even before his birth, he was designated to be adopted by Matsudaira Katsuyoshi, the daimyà  of Iyo-Matsuyama Domain and this was officially announced on November 25, 1837.
However, on July 27, 1838, Matsudaira Narisawa, the young daimyà  of Fukui Domain, died suddenly without an heir. His sister, Asahime (the widow of Narisawa's predecessor), and his brothers, Shà Âgun Tokugawa Ieyoshi and Tokugawa Nariyoshi, agreed that Kinnojo should become the next daimyà  of Fukui. After his genpuku ceremony, he took the name Matsudaira Yoshinaga, having been granted one kanji from Ieyoshi's name. At this time, he was granted the court rank of Senior Fourth Rank, Lower Grade and his courtesy titles were Echizen-no-kami and Sakon'e-no-gonshà Âjà Â. On April 6, 1839, he was married to Yu-hime, a daughter of Hosokawa Narimori of Kumamoto Domain.
In 1839, Yoshinaga began implementation of a fiscal austerity plan in an effort to resolve the perennial financial difficulties of Fukui Domain. He began by cutting the stipends for all of his samurai retainers in half for a three-year period, and also his own expenses for five years. In January 1840, with the discharge of Matsudaira Shume, reformists such as Nakane Yukie, Yuri Kimimasa and Hashimoto Sanai took a leading role in domain politics. Yoshinaga performed innovative work such as establishment of a translation bureau "Yoshà Â-shà «gaku-sho" to acquire rangaku knowledge and spur military modernisation. He built a modern armaments factory, and the Meidà Âkan han school was nationally recognised. A bussan-shokaijà Â, or cooperative venture between the domain and wealthy merchants also contributed to the domain's economic recovery. In 1851, he was promoted to Sakon'e-no-gonchà «jà  and Senior Fourth Rank, Upper Grade.
In 1853, in the aftermath of the Perry Expedition to demand an end to Japan's national isolation policy, at first Yoshinaga joined the anti-foreigner party led by Tokugawa Nariaki (daimyà  of Mito Domain) and Shimazu Nariakira (daimyà  of Satsuma Domain). However, later he changed his position to opening the country to foreign trading after contact with the rà Âjà « Abe Masahiro.
When the succession problem of 14th Shà Âgun arose, he delegated his retainer Hashimoto Sanai to Kyoto in support of Tokugawa Yoshinobu, the lord of the Hitotsubashi-Tokugawa family. However, with the appointment of Ii Naosuke to the position of Tairà Â, Yoshinobu's faction was defeated and Tokugawa Iemochi (of the Kishu-Tokugawa family) became Shà Âgun. The Ii clan of Hikone Domain and the Echizen-Matsudaira clan of Fukui Domain had had a strong enmity for several generations, and relations between the Tairà  worsened further after Ii pushed through the ratification of Treaty of Amity and Commerce between US and Japan without acceptance by Emperor Kà Âmei. Infuriated, Yoshinaga intruded into Edo castle with Tokugawa Nariaki to protest against Naosuke's actions. On 5 July 1858, he was forced to resign as daimyà  of Fukui Domain as part of the Ansei purge. At this time, he took the name "Shungaku".
The assassination of Ii Naosuke in the Sakuradamon Incident changed the Shogunate's policy, allowing Matsudaira Shungaku to return to politics in April 1862. He strongly supported the kà Âbu gattai movement to strengthen relations between the shogunate and the Imperial court. He was appointed to the newly created post of Seiji sà Âsaishoku, a high-ranking government oversight position and worked with Matsudaira Katamori (daimyà  of Aizu Domain), who was appointed Military Commissioner of Kyoto, in charge of security for the Emperor. In 1862, Shungaku formed the Rà Âshigumi, a group of rà Ânin organised as a paramilitary militia to help guard Shogun Tokugawa Iemochi on his 1863 trip to Kyoto. He also invited Yokoi Shà Ânan from Kumamoto Domain as a political consultant, and planned for Shogun Tokugawa Ieshige to relocate to Kyoto. These actions were known as the Bunkyà « Renovation after the Japanese era name. In 1863, the Rà Âshigumi were transformed into the Shinsengumi. Matsudaira Shungaku moved to Kyoto the same year, but the increasing strength of the Sonnà  jà Âi movement led by Chà Âshà « Domain forced him into increasingly unfavourable compromises, and he was forced to resign as Seiji sà Âsaishoku in disappointment.
Shungaku returned to Fukui, and from June 1863, began preparation to raise an army consisting of all of the samurai of Fukui Domain, which would march on Kyoto and would be led by Matsudaira Mochiaki. Although Satsuma Domain, Kumamoto Domain and Kaga Domain were amenable to the idea and there was no immediate opposition from Emperor Kà Âmei, his appeals to other domains went unanswered and the shogunate was not supportive, so the proposed coup never took place. Instead, there were increasing acts of assassination against members of the Tokugawa clan by pro-Sonnà  jà Âi rà Ânin.
After purge of Chà Âshà « Domain by Aizu Domain and Satsuma Domain (the coup of 18 August) and the Kinmon Incident, Matsudaira Shungaku returned to Kyoto in 1864 as a member of the Sanyo Kaigi (Ã¥ÂÂé Âä¼Âè°), a short-lived consultative assembly consisting of Tokugawa Yoshinobu, Shimazu Hisamitsu, Date Munenari, Matsudaira Katamori and Yamauchi Yà Âdà Â. This congress intended to diminish the power of the Shogunate and establish a council system of government by the Imperial Court together with select major domains. Meetings were held eight times at Shungaku's residence, and discussions were held on the opening of Hyogo (Kobe) Port to other nations and on how to respond to the threat posed by Chà Âshà « Domain. The system did not function well because of conflicts between the members, especially the personal enmity between Shimazu Hisamitsu and Tokugawa Yoshinobu. On 22 March 1864, Shungaku replaced Matsudaira Katamori as Military Commissioner of Kyoto, but he resigned on 7 April.
In October 1867, Yoshinobu resigned as shà Âgun, returning political power to the Imperial court, but tried to maintain Tokugawa hegemony as the most powerful of the feudal lords. In the subsequent Boshin War, Shungaku acted as an intermediary until the final surrender of the pro-Tokugawa forces in 1869. In 1868, his court rank was elevated to Junior Second Rank, and his courtesy title to Gon-Chà «nagon. His court rank became Senior Second Rank in 1869.
In the new Meiji government Shungaku served in a number of cabinet-equivalent posts, including Chief Executive of Internal Affairs, but soon resigned all posts in protest at the domination of the Meiji government by members of the former Chà Âshà « and Satsuma domains.
In 1870, Shungaku invited William Elliot Griffis to Japan as an oyatoi gaikokujin to teach in Fukui.
Together with Ikeda Mochimasa and Date Munenari, he helped write the Tokugawa reiten roku, a compilation of records of Tokugawa shogunate ritual protocol, in 1881. He was also awarded the Order of the Rising Sun, second class in 1881 and his court rank was raised to Junior First Rank in 1888. He was awarded the Order of the Rising Sun, first class in 1889.
Shungaku died aged 63 in 1890. His death poem is "Even if I become one of countless souls, I would soar up to heaven and protect the Emperor's reign for our nation (Naki-kazu-ni/Yoshiya-iru-tomo/Amakakeri/Miyo-wo-Mamoramu/Sume-kuni-no-tame)". His tomb is located in the temple Kaian-ji in Shinagawa, Tokyo.