When the issue of religion is contemplated in Nobunaga's life, people tend to dismiss the whole thing claiming that he was an atheist, or, even better, they quote the whole deal with the self-deification at Azuchi, turning him into a heretical megalomaniac.
The words of Luis Frois on the issues and Nobunaga's constant (and brutal) persecution of Buddhist confederates are usually reported ss evidences of such a theory.
In a correspondence with a fellow missionary dated 1569, Frois wrote that "he openly declares that there is no creator of the universe, no immortality of the soul, no life after death", speaking about Nobunaga's beliefs, portraying him as a lost cause for what concerned Catholicism.
The reports of Frois sure gave us an impression, but we must not forget that Nobunaga was not a Westerner, so trying to define his spiritual disposition from a Catholic point of view may be quite tricky.
Of course I'm not stating that Nobunaga was as a fervently religious person as Uesugi Kenshin or Takeda Shingen were (both of them received monastic education), but that we can't really describe him as an "atheist" (or even as a "satanist", as popular culture taught us) according to our modern standard, despite his verified pragmatism and unorthodox solutions when it came to del with the Ikko Ikki & Co.
First of all, we don't have to identify the concept "religion" as a mere matter of "believing in supernatural entities".
Religion is, firstly and foremost, a "cultural matter".
Giving a trascendental or mystic outline to the identity of a community is the first step of human civilization, it's how people recognize themself as part of a "society".
The "rules" according to which this society develops derive from some kind of "mythology" that legitimizes its identity, and sometimes superiority, among "others".
It's the same for every monotheistic religion, but this basical anthropologioc principle applies to ancient Greeks, Egyptians and of course even to Shintoism, the indigeous religion of Japan.
During Nobunaga's time, the religious compartment was shared between Shintoism and Buddhism.
As Shintoism was the religion more popular with the low classes and rural society, because of its emphasis on family, ancestors and farming, Buddhism was the religion of the warrior class; it was common to have the kids of a samurai to study in a Buddhist temple so to apprehend what the warlord of the time considered as "ethic": value the loyalty to superiors, need for decorum and feelings of superiority for those who didn't belong to the samurai class.
Even Nobunaga received such an education. It's said that he studied in a temple by Kiyosu castle, and the influence of Takugen Shuon, a bonze of the Rinzai sect, over Nobunaga and the Oda family is well-known and documented.
It's him who suggested the name "Nobunaga" for the boy's genpuku to Nobuhide, Nobunaga's motto "Tenka Fubu" and, according to certain sources, even "Gifu" when it came to rename Inabayama castle.
Other Zen "teachers" whose friendship Nobunaga could boast were Nange Genkō, a patron of arts and fine culture, and Sakugen Shuryo, famous for his diplomatic relationships and missions in China, but they'll get later in the picture.
Sure, we don't know who took care of Nobunaga's education at the time, but we know that he spent the most of time having fun with his band of kabukimono rather than studying Confucianism, subject that he was quite acknowledged about, anyway.
The idea is that of a "country boy", a description that accompanied Nobunaga during most of his youth and even during his first clashes with powerful daimyo.
Sure his behavious do suggest a lack of higher education, but in my opinion the source of this "wildness" is to find in Shinto.
As I said previously, Shinto religion covered those sides of a Japanese daily life that dealt with with traditional, "regional" issues.
Praying for protection against famine, illness and the like was supposed to be a Shinto duty because of the "local character" of such issues.
Nobunaga had a strict connection with Shintoism through his whole life.
In his youth he was known for being a faithful attendee of the Tennou Matsuri of Tsushima shrine (津島神社).
The festival honors Gozutennō, invoked against pestilences during summer, but it mostly focuses on celebrating the Tennō river, which course is animated by the floating of suggestive makiwara-bune, rappresenting the five villages that once formed Tsushima.
Of course I'm sure that his "devotion" here was mostly due to the appeal of the joyous festival more than genuine religious fervor, but you can say that this experience formed the conscience of Nobunaga, who saw religion as a way to give the sense of "kinship" through culture rather than politics.
Speaking of Gozutenno, it's worth mentioning the attendance of Nobunaga and his men to the Gion Matsuri in 1578.
Gion and Tsushima are connected as both festivals share the same origin of protection against pestilences, and in both festivals the support of Susanoo is invoked to keep in place a rampaging Gozutenno.
During the Gion Matsuri, Nobunaga enjoyed the view of the yamaboko parade, but also gave a splendid example of modern "public order" management, so that everyone could enjoy the festival without its rituals being interrupted or disturbed.
The other important Shinto temple strictly connected to Nobunaga's name is the Atsuta shrine (熱田神宮).
This famous shrine was originally built to host the Kusanagi sword, one of the three Imperial treasures, but it's now also the house of the Five Great Gods of Atsuta, or those deities connected with the legendary sword and the foundation of the shrine: Amaterasu, Susanoō, Yamato Takeru, Miyasuhime and Inadane.
Nobunaga came here to pray for victory on the way to the battle of Okehazama in 1560, and returned once his wish was granted to build a roofed wall hardened by mud, grease and lime, the "Nobunaga Wall" (信長塀), as a token of his gratitude.
Many legends are connected with Nobunaga's visits to Atsuta Shrine.
One refers to the Makezu no Tsuba and tries to explain the use of the eiraku coins, bringing in an exquisitely Buddhist explanation, another, more suggestive and tied to Shinto symbology, talks about two white egrets that took flight from the temple once Nobunaga and his army were done with the rituals, only to rest by the camp of Imagawa's forces, showing Nobunaga's army where the enemy was posted.
Like many other animals, egrets are considered messengers of kami, and for this reason also frequently used as an "offer" to a temple.
Even if a mere legend, the story of the egrets is a perfect example of cultural intermission on a political matter, and how a "religious" fact legitimized an historical fact.
Another Shinto shrine is mentioned when it comes to Okehazama, at least on Nagoya's touristic guides, the Hioki shrine (日置神社).
It's said that Nobunaga made a stop to pray here too, and after his victory he donated a thousand pine branches to the shrine.
It's worth noting that the deity enshrined here is Futodama, the kami to whom the Inbe clan traced its descent.
Since we mentioned the Inbe Clan we are now forced to step back and return to Nobunaga's ancestors, who claimed Tsurugi shrine(劔神社), another Shinto shrine, as their "home".
It's said that Nobunaga kept on referring to Tsurugi shrine as the shrine of his ancestors too, but unfortunately we have no mentions of a visit there, obviously because the shrine was part of enemy terrority back then.
The shrine is dedicated to Susanoo.
Browsing through the pages of the Shinchoukoki, we can find many other examples of the same kind.
They are important statements that, if Nobunaga wasn't a follower of any religion, he did understand its importance in the social structure, identity and tradition of "his people".
It's reported that in 1574 Nobunaga happened to be in Kyoto during the Kamo Matsuri at Kamo Shrine (賀茂神社).
This Shinto sanctuary complex houses one of the most important festivals of Kyoto, that in Nobunaga's times was referred as "Kamo Matsuri", but that now is famous as the "Aoi Matsuri": originally a festival to grant a bountiful harvest, it was celebrated through ritual horses races and equestrian archery.
The priests asked him if he could provide some horses for the races: Nobunaga granted them two of his favourite war horses that he personally rode in battle, and another eighteen, all of them "outfitted splendidly", so that the festival left a deep impression on the visitors.
In 1575 he happened again around the Atsuta grounds while camping there during the campaign against Takeda.
He was observing the Hakkengu (八剣宮) and noticed that it was in pitiful conditions: he promptly ordered Okabe Mataemon to take care of its reconstruction.
It wouldn't be the last time that Nobunaga cared to support and fix famous shrines of Shinto faith.
In 1579 it came to Nobunaga's attention how the wooden gutters of the Iwashimizu Hachiman Shrine (石清水八幡宮) rot, ruining the whole "character" of the shrine.
He summoned his deputies of the province, and had them work on a project using bronze gutters, so that the job could last "for ages".
The work proved quite expensive and time consuming, but once it was done, a groundbreaking ceremony was held after receiving the blessing of the Emperor, and Nobunaga presented the temple a refined censer.
It's interesting to note that another wall, exactly like the one at Atsuta Shrine, was built here by Nobunaga.
In 1582, a request from Uwabe Sadanaga, one of Nobunaga's retainer, was brought to his attention by Hori Hidemasa: "the custom of rebuilding the Grand Shrines of Ise (伊勢神宮) every twenty years had been in decline for three centuries and was no longer being carried out".
I don't think that I need to tell you about the Ise Shrine. And Nobunaga either, needed to be asked twice: but this time, aware of the expenses after the deal with Hachiman Shrine, he asked Nobutada to contribute with Gifu's funds so to not "impose hardships on the populace".
I talked about Shinto, and now I'll spend a few words on Buddhism too, to close the circle.
I already mentioned his Buddhist intimate friends and "teachers" and even Frois reported that Nobunaga described himself as a follower of the Hokke sect of Buddhism, even if it's usually considered as a misunderstanding on Frois' account.
Truth is that the Buddhist temples where he usually lodged at during his trips to Kyoto belonged to the Hokke sect: I'm talking about the Myokakuji (妙覚寺) and the Honnoji (本能寺), the temple that in 1570 he claimed as his ryoshuku, or "private quarters".
It's usually assumed that Nobunaga favoured those places because the quality of the hospitality rather than the religious affiliation, but it's worth mentioning that it may be true also otherwise.
After all, the temples that Nobunaga built for his family and clan were of Buddhist affiliation: the family temple that he built at Azuchi, the Sokenji (総見寺), was a temple of the Rinzai sect of Buddhism, and an image of Kannon was enshrined there; the Sofukuji (崇福寺), the temple that he used when he moved to Gifu, belonged to the Rinzai sect of Buddhism too.
It's worth noting that also the temple that he built in 1553 to honor the memory of his former tutor Hirate Masahide, the Seijouji (政秀寺), was of Rinzai affiliation, while the Banshoji (萬松寺), the family temple built by Nobuhide in 1540, was of Soto sect.
After Nobunaga's death, many temples were dedicated to his memory.
The Sokenji (総見寺) in Nagoya was originally built in Kiyosu, and was dedicated to his father and brother's memory by Nobukatsu after their death at Honnoji. Like its homonimous in Azuchi, the temple belongs to the Rinzai sect of Buddhism.
In 1587, Hideyoshi dedicated the Daiun-in (大雲院) to the memory of Nobutada and Nobunaga: "Daiunin" is the posthumous Buddhist name of Nobutada.
Another Buddhist temple that hosts a memorial of Nobunaga is the Amidaji (阿弥陀寺), a temple of the Jodo Sect in Kyoto: it's said that the monk Seigyoku, who had deep connections to the Oda family, gathered the remains of Nobunaga, Nobutada and the other men who met their death at Honnoji and buried them in the temple grounds: the ashes have been equally divided through the temples of Amidaji, Honnoji and Kenkun Shrine (建勲神社), which is the most recent temple dedicated to Nobunaga: this Shinto shrine was built in 1870 by one of Nobunaga's descendant, Oda Nobutoshi, with the blessing of Emperor Meiji, and Nobunaga himself is enshrined here.
Long story short, Nobunaga wasn't an iconoclast, an atheist or a rebel like many likes to think to justify this or that "cruelty".
He never denied the importance of religion or vilified its contents: whenever he condamned or executed a religious group or personality, it was simply because "they no longer stressed the moral practices of the nembutsu path", they "disobeyed even the ordinances of their own school" or they "were concerned only with wordly affairs".
To put it in simple words, they were acting like a political force, and not like a religious entity.
PS: Since last time I've been scolded for the lack of bibliographical references, here you go:
"Religion in Japanese History", Kitagawa, Joseph
"Feste Tradizionali in Giappone", Caillet, Laurence (trad. Dentoni, Francesco)
"Oda Nobunaga and the Buddhist institutions", McMullin, Neil Francis, which can be consulted online here.