Masayuki Sanada

Masayuki Sanada is the fourth head of the Sanada clan and the father of Lady Muramatsu, Nobuyuki, and Yukimura. His older brothers are Masateru Sanada and Nobutsuna Sanada.  He is a shrewd yet masterful strategist who is famous for stopping Hidetada Tokugawa's 38,000 men army with a mere number of 2,000 at Ueda Castle. Outside of battle, he was known for his cunning and sly nature, which was respected by both Hideyoshi and Ieyasu. It was thanks to his quick thinking that allowed the Sanada to survive the entire conflict of the Sengoku period with their domain still intact.

Before his playable appearance in Samurai Warriors, Masayuki has been a generic NPC since its starting entry. This character interpretation shares a duet with Yukimura called Akazonae Tenkaichi ~Sanada Oyako Special Version~.

His Nobunaga's Ambition counterpart is fifth place in Gamecity's character popularity ranking for 2015. He placed first in the Nobunaga no Yabou Taishi poll for most favorite father; fans voted him sixth for the best leader poll and fourth for best subordinate.

Samurai Warriors
The series initially presents him as an elderly or middle-aged general who serves the Takeda. In most titles in the series, he orders Yukimura to assist him in halting the Tokugawa forces at Ueda. Samurai Warriors has him trap Ieyasu and his men by luring them downstream from the castle and breaking the floodgate to the river. If the attack succeeds, Ieyasu will lose many of his men and a great deal of morale.

Samurai Warriors 2 has him prevent Hidetada from reaching Sekigahara by stalling the Tokugawa army at Ueda Castle. He is a commander during the Fall of the Takeda who remains hidden in the main keep until the end of the battle. Masayuki assists the fictional Edo Castle in Kanetsugu's and Keiji's story mode. Nagamasa's dream stage has him appear with the Takeda to defeat Nobunaga. In Ina's dream stage, he is a crocked grandfather who is driven back by his daughter-in-law.

The fourth title dedicates a cutscene of Masayuki congratulating his sons for their efforts at Kanagawa, which paved the path for Sanada independence. He assigns his sons their respective paths for their family before choosing to settle their family at Ueda Castle.

Spirit of Sanada faithfully depicts Masayuki's historical exploits many of which were previously assigned to his sons in the series. As the main protagonist of the game, he first appears under Shingen Takeda's tutelage at Kawanakajima and a friend of the lord's son Katsuyori Takeda, where after completing some transporting of supplies as ordered by his father, he joins the battle at Mt.Saijyo, defending Shingen in the fabled duel against Kenshin, where he uses explosives at Kenshin's mount to force him to retreat. Despite many Takeda officers such as Kansuke and Nobushige dying, the Takeda score a victory in a showdown at Kawanakajima, thus improving his standing. After returning home, Masayuki is welcomed by his new infant children. Happy beyond belief, he swears to remain alive to make sure he is able to watch over them.

The peace does not last long as the Takeda's ally, Yoshimoto Imagawa, was killed at Okehazama, essentially destroying all power the clan had. Because of this, the clan becomes split over aiding the Imagawa and their allies, the Hōjō or exploiting Yoshimoto's death and taking his heir's land. When Shingen ultimately invades Imagawa territory at Suruga, Yoshinobu, the eldest son of Shingen opposes the decision vehemently and is subsequently executed for treason and rebellion. After dealing with the Imagawa, Shingen begins his march to Kyōto. Barring his path is Ieyasu Tokugawa, Nobunaga Oda's ally. Despite numerous defeats in the lead-up and at Mikatagahara, Ieyasu is able to evade Masayuki's grasp. Shortly after the triumph at Mikatagahara, Shingen dies to illness, forcing the entire Takeda army back to Kai.

Trying to calm an enraged and shaken Katsuyori, he nevertheless accompanies his new lord on the siege of Nagashino, but warns his lord to not engage with Nobunaga's reinforcements. While their siege is strong, the Tokugawa refuse to break, and Nobunaga's reinforcements finally arrive to relieve their allies. Against Masayuki's wishes, Katsuyori engages the Oda in open battle at the nearby Shiratagahara. As Masayuki had predicted, Nobunaga was able to counter the Takeda cavalry via mass palisades and rifles. Masayuki is barely able to get Katsuyori to escape back to Kai, at the cost of Masayuki's brothers and many other key Takeda generals. With the Takeda in decline, Masayuki nonetheless serves faithfully and aids Kagekatsu Uesugi during the Otate war, and sends his children to Azuchi Castle to ensure his clan's safety. Numata Castle, near the Sanada's territory of Ueda, is also successfully captured by Katsuyori.

After the Ōtate Rebellion, the Oda-Tokugawa Coalition begin invading Kai. With castles falling left and right, Katsuyori is pushed by Nobushige Oyamada and Katsusuke Atobe to head for the newly-built Shinpu castle to resist the Oda. Masayuki, however, does not believe in the castle's ability to hold out against a siege and wishes for Katsuyori to seek refuge at Ueda and to abandon Kai. Agreeing to Masayuki's plan, Katsuyori sends Masayuki back to Ueda in advance to prepare for his arrival. During Masayuki's preparations, however, Kunoichi delivers a letter from Katsuyori; Revealing that he believed the Takeda's demise was inevitable, and, hoping to not involve the Sanada further, has gone to Shinpu castle. Kunoichi also reports that Oyamada had betrayed Katsuyori, and that their lord was now dead and the Takeda had been eradicated. Thrown into an angry flurry, Masayuki is unable to understand why his lord would give up so easily, but being reminded of his children, he returns to his calmer demeanor and swears to make it out alive. After Katsuyori's death, Masayuki personally meets and submits to the Oda with Ieyasu acting as the audience to the surrender. Although Ieyasu wishes for Masayuki to live on for the sake of those that died in his place, Masayuki warns Ieyasu to not use the dead as an excuse for his ineptitudes.

As part of his submission, Yukimura and Muramatsu are sent to Azuchi Castle as hostages. Not long after, Nobunaga is killed by Mitsuhide Akechi at Honnōji, and the city is overrun by Akechi troops. Fortunately, both of his children are rescued and return to Ueda safely.

Masayuki soon gets warped into the Tensho-Jingo conflicts around Kai province, where due to the death of Nobunaga, his officials lose control. Taking advantage of the conflict between the Oda and Hōjō, Masayuki attacks Kazumasu Takigawa, the guardian of Numata Castle. As the Hōjō would be discontent at the castle being seized at their expense, Masayuki pledges loyalty to them to keep them appeased. Masayuki then predicts an upcoming battle between the Hōjō and the Uesugi soon after. With Ujimasa and Kagekatsu signing a peace accord, the next battle shifts to Ieyasu once more, hoping to use the conflict to raise the Sanada name. Secretly, he also makes secret deals with discontent officers of the Hōjō to have them eventually break away and aid the Sanada instead.

Masayuki soon betrays the Hōjō to ally with the Tokugawa, and he beats back the Hōjō at Numata Castle. Once the situation stabilises, the Tokugawa ally with the Hōjō and order Masayuki to yield Numata over to the Hōjō. Not wishing to follow through, Masayuki hastens the construction of Ueda Castle and sends Yukimura to forge an alliance with the Uesugi. With Ieyasu aware of Masayuki's wavering loyalties, he launches a siege on Ueda. Thanks to the castle's defenses and his own strategies, Masayuki and Yukimura prevail against the odds.

Learning of Masayuki's resounding victories against the Hōjō and the Tokugawa, Masayuki is personally summoned by Hideyoshi to Ōsaka to discuss an alliance. Yukimura is then left at Ōsaka as a hostage of the Toyotomi, with Masayuki being seen off by Mitsunari Ishida, who guarantees Yukimura's safety, but warns Masayuki to not get any second thoughts about allying with the Toyotomi. As part of their servitude to the Toyotomi, the Sanada are told act as the Tokugawa's yoriki. Although there is no hostage as part of the agreement, Nobuyuki volunteers to go meet the Tokugawa as a safety measure in the case something abrupt were to happen to the Toyotomi. Masayuki, proud of his son's growth, allows him to decide for his own.

After that resounding victory, the Hōjō are soon the only clan who have not submitted to Toyotomi. Masayuki opts to fan the flames further by intentionally getting Kuninori Inomata to attack Numata Castle, giving the Toyotomi the needed justification to launch their conquest of Kantō. He rejoins his family and Toshiie Maeda to besiege the last of the Hōjō castles on the way to Odawara Castle. Seizing the castles of Matsuida and Hachigata, Masayuki is able to break the morale of many of the Hōjō's officers to get them to surrender. In the upcoming Hachioji battle, however, Toshiie gives the order to slaughter any that oppose them. Masayuki, however, disobeys orders and continues to accept surrendering officers, much to Toshiie's relief. Nonetheless, the battle results in the deaths of many civillians and soldiers. After the battle, he discusses with Nobuyuki over the situation. Although Nobuyuki sees the bloody result as a necessary sacrifice to hasten the peace, Masayuki expresses the disdain for "necessary sacrifices". Once Odawara falls, the land is united and Nobuyuki is left to become the lord of Numata, and Masayuki opens up at how he had sacrificed the men of Numata and Hachioji to achieve their goals to Yukimura. Predicting a major event to occur, he has Yukimura return to Osaka as a hostage in order for him to monitor the situation up close.

Hideyoshi's death soon leads to the land being divided into two factions, with Mitsunari Ishida of the West against Ieyasu Tokugawa, of the East. Masayuki allows Nobuyuki Sanada to remain with the Tokugawa due to his marriage with Ina and support for Ieyasu, but allies himself with Mitsunari before pushing Yukimura to make his own choice. Ultimately, Yukimura chooses to stay with his father and the two prepare themselves for Hidetada's eventual arrival. Fighting against the Tokugawa, he assigns a new ward at Ueda, and makes it his job to delay Hidetada Tokugawa from arriving at Sekigahara. Beating back Hidetada, he actually manages to have Hidetada on the retreat, even to his surprise and commits a pursuit, nearly having Hidetada's head, if not for news of the Eastern Army's victory at Sekigahara. After this, he and Yukimura are considered for execution, but instead exiled to Mt. Koriyama, where Masayuki dies without much fanfare. In his last moments, he wonders if this is karma for failing show enough conviction to Katsuyori to convince him not to give up but is content having seen the growth of his children. Masayuki's defenses and ambush strategies are later used by Yukimura when he defends Osaka Castle as well as the creation of the impregnable Sanada Ward.

Warriors Orochi
In Warriors Orochi 3, if Yukimura is selected as one of the playable characters, Masayuki will be seen leading the Allied Forces against Kiyomori at Anegawa instead of Yukimura. He also has a comparatively young appearance compared to his generic model in Samurai Warriors 3,

Kessen
Although it isn't seen, Masayuki (called "Sanada" or "Masa Sanada" in the English version) easily stalls Hidetada's men during Sekigahara in Kessen. He leads a small yet sturdy cavalry unit and relies on high morale and low fatigue to win his battles. If Mitsunari wins Sekigahara, the Sanada forces will join his pursuit to capture Ieyasu's head. Otherwise, the player will see him on the Toyotomi side at Harima. Though he's proud of his son's prowess, Masayuki doesn't completely accept all of Yukimura's methods, such as depending on kunoichi and shooting rifles from horseback. He inevitably dies in the later stages of the game, either in battle or due to an assassination ordered by Hidetada.

In Kessen III, a somewhat younger Masayuki serves as an adviser and strategist for Katsuyori. He opposes Nobunaga by fleeing and luring his enemy into several ambushes. Once he's out of sight, he hides in waiting and blocks off the path to his lord. Word from the local townsfolk will reveal their locations and help win the battle.

Nobunaga's Ambition
Guruguru Dungeon Nobunyaga has Masayuki act as one of the key characters in the Sanyada Children's Day event. Masayuki personally ambushes Ieyasu and Nobunyaga during Nagashino. He perishes yet kills both of his foes. The protagonist's tea bowl resets time and eventually sends him/her to the Sanyada household prior to the battle. At his older brother's behest, Masayuki believes the stranger to be a traveling fortune teller and places his faith in his/her "divinations".

When he prepares to leave for the main lines of Nagashino, the protagonist stops him by imploring him to protect Katsuyori from enemy ambushes. Masayuki and Nobutsuna consider his/her words and switch places, resulting in his older brother's historical death. Masayuki is last seen preparing himself to lead his family. When the protagonist later learns he/she had been knocked out at the start of Nagashino by a Mikeda horseman, he/she wonders how much of his/her experiences with the Mikeda and Sanyada were real.

Development
Koinuma commented that Masayuki was the most requested playable character for the Samurai Warriors series prior to his debut. He always felt reluctant to include him, however, since most of his famous feats require heavy exposition and are too politically-minded for the typical Warriors action experience. He felt confident adding Masayuki in Spirit of Sanada because this game's presentation gives enough breathing room to explore his history. Koinuma conceived Masayuki's rivalry with Ieyasu and a "youthful, passionate image" to make him stick out from his stereotypical portrayals in other fictional mediums. His overall design theme was "to look like a tactician." Designers gave him his split-colored hair to indicate his two-faced nature and foreshadow the rift between his sons.

Personality
Masayuki is a crafty individual who has no qualms resorting to treacherous methods in order to ensure his clan's survival. This way of life is said to have a negative impact on the earnest Yukimura.

However, he is seen to be particularly close to the Takeda, especially Shingen and his son, Katsuyori. Despite his supposed nonchalant personality, his guilt for Katsuyori's fall is one of Masayuki's notable acts of conscience.

Character Symbolism
Masayuki is symbolized by the kanji for "truth" (真) and "interest" (興) as well as golden leaves.

Hakusan Gongen is a celebrated deity within the Shinbutsu-shugo faith who forms the namesake of Masayuki's first rare weapon; a gift made in the deity's image will also please him. His divine duty depends on the province worshiping him; he has been a white rabbit of ingenuity, a benign yet almighty guardian deity, a superior to three other deities, or a god of festivals. Before Masayuki established the Sanada clan's independence, his clan's previous residence was near Yamaga Shrine which was established in 718 to be a place of worship for Hakusan. The Sanada clan considered Hakusan their guardian deity and have prayed to him for many generations. Nobushige's devout faith in Hakusan led to legends about his now famous mantra behind their six coin crest (namesake of Masayuki's default weapon). Today, much of the Sanada territory has been relocated to be near Yamaga Shrine.

His second rare weapon is named after Nagi-jinja, a shrine dedicated to the famed strategist Kusunoki Masashige. Born in the 14th century, he fought for Emperor Go-Daigo in the Genkō War and won many victories with his tactics. More important than his achievements, however, was his undying loyalty to the emperor even when the latter forced him to deal with the much larger Ashikaga Takauji's forces directly. Masashige's death made him a martyr throughout the ages.

One of the gifts that Masayuki will give in Spirit of Sanada is a chestnut. Modern Ueda City harvests and sells chestnuts as a local crop. It's used for specialty jams or honey sold around Ueda Castle and other Sanada themed tourist areas. Chestnuts can represent luxury, fairness, and gratification within the flower language.

Voice Actors

 * Dan Woren - Samurai Warriors 3 (English)
 * Ron Halder - Kessen (English)
 * Munehiro Tokita - Samurai Warriors (Japanese)
 * Masaya Takatsuka - Samurai Warriors 2 (Japanese)
 * Takahiro Fujimoto - Samurai Warriors 3 (Japanese)
 * Kenta Miyake - Samurai Warriors: Spirit of Sanada (Japanese)
 * Yūgo Takahashi - Kessen III (Japanese)

Live Action Performers

 * Isamu Ishizaka - Butai Nobunyaga no Yabou Yukimura to Gorin no Ken
 * Yoshihiro Uemura - Makai ~Hoshi to Umi no Hangeki~, Makai ~Fukkatsu to Yabou Revival and Vision~
 * Daisuke Kikuta - Butai Nobunaga no Yabou Taishi Fuyu no Jin Oudou Shikkou ~Kiko no Shiroshio Hen~

Quotes
See also: Masayuki Sanada/Quotes
 * "Ha ha... Now I get to plot my revenge!"
 * "Amazing! I thought this castle was as good as mine!"
 * "I will crush this tiny castle!"
 * "The fool, he underestimates the strength of Ueda! Yukimura do just as we planned!"
 * Hidetada and Masayuki; Samurai Warriors 2


 * "We'll show the world how the Sanada fight... And send shockwaves through those lords who think the land is theirs. But you must watch me closely, Yukimura. Though you are already great, there are many things that even you can learn."
 * "Yes, Father. I am prepared to do just that."
 * Masayuki and Yukimura; Samurai Warriors 2: Empires


 * "Yuki! I'm giving command of our men to you. You will lead them into battle, Yukimura. Go and bloody Ieyasu's nose! And spread the glory of Sanada throughout the land!"
 * Speaking to Yukimura; Kessen

Ground Moveset

 * , undefined: Masayuki throws his axe up as it cuts enemies in midair, then he catches his axe and swings it right.
 * ,, undefined: Masayuki pierces his axe, sending a wave of energy forward.
 * ,, , undefined: Masayuki holds his axe then moves forward spinning it.
 * ,, , , undefined: Masayuki swings his left hand and ignites several explosions in front of him.
 * ,, , , , undefined: Masayuki spins his axe creating a tornado, then makes a plume of fire.
 * ,, , , , , undefined: Masayuki slams his axe into an enemy, then moves him/her around and throws him/her up.
 * ,, , , , , , undefined: Masayuki charges forward with his axe, then jumps and slams the ground, erupting lava.
 * ,, , , , , , , undefined: Masayuki spins his axe around himself, then catches it and thrusts it, bursting energy forward to blow back enemies.
 * Masayuki moves forward rapidly swinging his axe diagonally. He then finishes by spinning his axe above then catches his axe and does a powerful energetic slash.
 * (Ultimate/Kaiden): Masayuki cuts a large tornado around himself on the ground, then jumps and and slams the ground with his axe erupting a large rapid-hitting tornado.

Hyper Moveset

 * undefined, : Masayuki throws his axe upward spinning it in circles.
 * undefined, undefined, : Masayuki dashes forward ramming enemies with his axe.
 * undefined, undefined, undefined, undefined, undefined, : Masayuki spins around swinging his axe.

Horse Moveset

 * , undefined: Masayuki throws dynamite to the right.
 * ,, undefined: Masayuki swings his spear down.
 * ,, , undefined: Masayuki swings his spear up.
 * ,, , , , , , : Masayuki swings his spear up and down.


 * Deadlock Attack & Mighty Strike: Slams his axe down on the enemy, knocks him/her into the air, then spins his axe, juggling the enemy, then slams his axe down.

Rare Weapon Acquisition

 * Stage: Second Siege of Ueda - Battle of Ueda Castle

Birth
He was born the third son of Sanada Yukitaka in 1547, but the exact date is unknown. His childhood name was Gengorō (源五郎). At birth, he had no right to succeed his father because of his two older brothers, Nobutsuna and Masateru.

Takeda retainer
In 1553, at seven years old, he was sent to the Takeda clan's headquarters in Kai as a hostage. There he becomes part of the Okukinjūshū (奥近習衆), a group of six young servants close to Takeda Shingen. According to the Kōyō Gunkan, Shingen favoured him as he soon recognized that Masayuki's talents and insight rivaled those of his father Yukitaka. As such, he is sometimes included among the Twenty Four Generals, alongside his father and two older brothers.

In 1558, he became the foster son of the Mutō family, a branch of the Ōi clan, of which Shingen's mother descended from, and adopted the name Mutō Kihei (武藤喜兵衛). Towards 1564, he married Yamanote-dono (山手殿), a daughter of Uda Yoritada, who was a local lord of Tōtōmi Province. Later she gave birth to his two sons Nobuyuki and Nobushige. During this period, he participated in many battles under the Takeda clan, including the Fourth Battle of Kawanakajima (1561) and the Battle of Mimasetōge (1569). Also most importantly, from 1572 onwards, he joined Shingen in his campaign towards Kyoto against the Oda and Tokugawa clans and took part in the Battle of Mikatagahara (1573).

In May 1573, Shingen died amidst his campaign and so Masayuki continued to serve his heir Takeda Katsuyori.

In 1574, his father Yukitaka died. At that point, his eldest brother Sanada Nobutsuna had already succeeded his father as the head of the Sanada clan. However, during the disastrous Battle of Nagashino (1575) against the Oda clan, both his older brothers, Nobutsuna and Masateru, were killed, so he came back to Sanada clan and claimed his inheritance. In this, Masayuki supposedly had the support of Kōsaka Masanobu, who held Kaizu Castle in Northern Shinano and was also a chief retainer of the Takeda clan. Katsuyori accepted his claim without any qualms.

In 1579, a year after Uesugi Kenshin's death, an alliance between the Takeda and Uesugi clans was established. The following year, ordered by Takeda Katsuyori, Masayuki invaded western Kōzuke, which was a Hōjō domain at the time, and seized Numata Castle, putting it under control of the Takeda clan. The same year, he was appointed the title of Awa-no-kami (従五位下・安房守).

In 1581, he was ordered by Katsuyori to supervise the construction of the new Shinpu Castle at Nirasaki. In the same year, Numata Kageyoshi, former lord of Numata Castle, attempted to retake his old fief, but Masayuki schemed to assassinate him and thwarted his plans.

In April 1582, Oda and Tokugawa allied forces started an invasion of the Takeda territory. It is said that Masayuki had intended to shelter Katsuyori and advised him to abandon Kai Province and flee towards Sanada's domain in Kōzuke. Instead, Katsuyori decided to take shelter at Oyamada Nobushige's Iwadono Castle, but was betrayed and ultimately died at Tenmokuzan. After the fall of the Takeda clan, Masayuki yielded to Oda Nobunaga and was put under the orders of one of Nobunaga's chief commanders, Takigawa Kazumasu. Masayuki managed to retain most of his domain, but he had to abdicate Numata Castle to Takigawa Masushigue, Kazumasu's relative.

Tenshō-Jingo Conflict
However, Nobunaga soon died at the Incident at Honnō-ji on June 21st, 1582. Upon Nobunaga's death, Oda clan's grasp over former Takeda territories weakened. Amidst the chaos, Oda retainers who were assigned by Nobunaga to govern those territories, such as Mori Nagayoshi and Kawajiri Hidetaka amongst others, either fled or were killed by local insurrection. Seeing this, neighboring Tokugawa, Hōjō and Uesugi clans all started to contest this vacuum of power in Shinano, Kōzuke, and Kai provinces. This was called the Tenshō-Jingo Conflict.

On July 5th, Takigawa Kazumasu lost decisively against the invading Hōjō army at the Battle of Kannagawa. In that occasion, Masayuki actually escorted back Kazumasu's remaining forces through Suwa, in Shinano. Though, seeing this chance, Masayuki sent his uncle Yazawa Yoritsuna and took back Numata Castle. Also, he put his oldest son Nobuyuki in charge of Iwabitsu Castle, further reinforcing eastern Kōzuke. On July 10th, Uesugi Kagekatsu invaded Northern Shinano. Masayuki sided with the Uesugi initially, but a couple of weeks later he defected to Hōjō's side. Both Uesugi and Hōjō's armies came to face each other at Kawanakajima on July 30th, but direct combat was avoided as the Hōjō army turned back and advanced south towards Kai province, which was in turn invaded by Tokugawa forces. Meanwhile, one of Uesugi clan's major retainer, Shibata Shigeie, revolted and Uesugi's forces also had to turn back from Northern Shinano to deal with it. At one point, the Hōjō had come close to controlling most of Shinano province, but then in October, Masayuki suddenly betrayed them, providing help to Yoda Nobushige, a local lord who had been resisting against Hōjō's advances under the Tokugawa banner at Kasuga Castle. He then officially defected to the Tokugawa's side. Faced with this development, Hōjō Ujinao saw his position in the conflict weaken and decided for a peace treaty and further alliance with the Tokugawa clan. This event marked the end of the conflict which lasted for roughly 5 months after Nobunaga's death. Masayuki was now a vassal of Tokugawa Ieyasu.

Confrontation with the Tokugawa
In 1583, Masayuki started the construction of Ueda Castle and the surrounding town. It became the headquarters of the Sanada clan in the following years.

In 1584, Tokugawa Ieyasu lead his army west towards Owari province in the Battle of Komaki and Nagakute against Hashiba Hideyoshi. Masayuki was left in northern Shinano to keep the Uesugi clan in check and took this opportunity to subjugate small, neighboring landlords and consolidate his power in the region. In December, as Ieyasu made peace with Hideyoshi and returned to his territory, he was pressed by Hōjō Ujinao to act on the terms of their treaty.

In that treaty, among other terms, Tokugawa Ieyasu agreed to transfer Numata Castle and its adjacent lands in Kōzuke province to the Hōjō clan. In April 1585, Ieyasu advanced his army into Kai province in a move to pressure Masayuki into abdicating Numata Castle. Masayuki however, resisted having to hand it over, having conquered it with great effort years before. Ultimately, he decided to cut relations with Tokugawa Ieyasu and once more switched allegiances by sending his second son Nobushige to Uesugi Kagekatsu as a hostage. With this move, he effectively joined Hashiba Hideyoshi's side, which opposed the Tokugawa-Hōjō alliance.

Months later, Tokugawa forces invaded Sanada clan's territory in northern Shinano province with 7,000 men and laid siege to Ueda Castle, which was defended by only 1,200 soldiers. However, Masayuki was able to inflict 1,300 casualties on Tokugawa's side and won a decisive victory. Meanwhile, Hōjō Ujinao attacked Numata Castle, but was also rebuffed by Sanada forces. This was the First Battle of Ueda Castle, a victory that earned Masayuki national prominence. Following this, Masayuki went from being just a former Takeda retainer to become recognized as an independent daimyō.

Under Toyotomi regime
Following his victory over the Tokugawa clan, Masayuki became a vassal to Toyotomi Hideyoshi. In doing so, he sent his son Nobushige (at the time a hostage to Uesugi clan) as a hostage to Osaka.

In 1586, the Hōjō clan try to take Numata Castle once more, but again they are repelled. Tokugawa forces also gather and march towards Ueda Castle again, but Toyotomi Hideyoshi interposes. At this point, Hideyoshi's political presence in Japan is too strong for the Tokugawa clan to oppose, and at his mediation, the attack is called off. However, he also designates Masayuki as a backup power to the bigger Tokugawa forces in the region. This effectively means that Masayuki now responds to Tokugawa Ieyasu in all military matters.

The following year, 1587, sees Masayuki traveling to Sunpu to meet with Tokugawa Ieyasu. Then, he goes to Osaka to be received in audience by Toyotomi Hideyoshi, and thus formally become a vassal of the Toyotomi regime.

Two more years would pass until the dispute between the Sanada and Hōjō clans involving Numata Castle and adjacent areas would be mediated by Hideyoshi and resolved. In 1589, Hideyoshi decides the Sanada clan would relinquish all of its domain east of Tone River, including Numata Castle, to the Hōjō clan. In turn, he granted them some territory in southern Shinano. However, by the end of that year, Inomata Kuninori, a retainer from the Hōjō clan who was now holding Numata Castle, is deceived into attacking the nearby Nagurumi Castle, located west of Tone River and defended by Sanada forces. The attack is successful and the castle is seized by Hōjō forces, but by this time, Toyotomi Hideyoshi had sanctioned a rule which prohibited daimyōs from engaging in battle over private disputes. This incident fully breached this rule and it would go on to become the reason of the Siege of Odawara in 1590, and the subsequent fall of the Hōjō clan.

After Hideyoshi's death in 1598, Masayuki joined Ishida Mitsunari's side during the Battle of Sekigahara. Masayuki sent his eldest son, Nobuyuki, to the eastern side, while Masayuki and his younger son, Nobushige, fought on the western side, a move that ensured the Sanada clan's survival. Fortifying Ueda Castle, Masayuki fought against Tokugawa Hidetada's 38,000 men with only 2,000 soldiers. This was the Second Battle of Ueda Castle, and, whilst it was not exactly a victory, Masayuki was able to deliver a heavy blow to Hidetada and delay his forces for long enough that they were unable to show up at the main battlefield on time.

However, the western side, led by Ishida Mitsunari, lost the main battle, and the victorious Tokugawa Ieyasu was able to redistribute fiefs at will. Masayuki and Nobushige were initially going to be executed, but, given Nobuyuki's participation in the eastern army, they were instead exiled to Kudoyama in Kii province. The Sanada clan was inherited by Sanada Nobuyuki.

Sanada Masayuki died in Kudoyama in 1611.