This relates (at first) to the experience of missionaries within Japan at the outset of proselytising activities. At the time, religion and belief had reached their apex. Kyoto was the centrepiece for a number of theoretical and philosophical debates on the nature of belief among various sects. As people became more familiar with the content of debate, this laid the foundations for the emergence of certain cultural traits. Those raised under the auspices of Buddhist faith might at times argue with the message spread by Christian missionaries, whilst others might be persuaded by the message of Christ and choose to convert to Christianity. It was in this environment, says Prof Kanda, that the Japanese began to conceive of the message of Christ as being similar to that of Buddhism (a philosophy closer to their own experience). The Japanese had been, from times past, multi-theist, a trait that could be said to be either a sign of curiosity or superficiality. As such, it has been assumed that the monotheistic religion of Christianity would have been an anathema to them. Yet the reaction of the Japanese to Christianity suggests otherwise. Another assumption has been that the Japanese at the time did not really understand the message being promoted by the missionaries, yet Prof Kanda doubts whether this was really the case.(50)

The missionaries themselves had stated that they believed that (the content of ) Japan`s original religions resembled the teachings of Christianity. The missionaries would not go so far as to say they were identical, and claimed that other faiths were `heresy` devised by the devil. Yet observations pointing towards similarities with Japanese religion meant that, at first glance, both Christianity and Japanese faiths were similar in message and form. One of those expressions deemed most important to the spread of Christian teachings, which in itself was founded in traditional Japanese ideals, was that of `Tendō` (天道), or `the way of heaven`. This expression was widely used during the Sengoku period, so much so that in the `Nippō Jisho`, a Portuguese-Japanese dictionary compiled at the beginning of the seventeenth century, the description given to the concept of `Tendō` (or Tentŏ as written in the dictionary) stated that this was `the way of heaven, both referring to heaven`s precepts and logic. We refer to God in this manner, and it is difficult to conceive of other religions using the term for anything other than that described above (i.e in reference to a deity)`. As far as the missionaries were concerned, the concept of `Tendō` was equal to that of God. Yet they did not believe the concept of God existed within the Japanese in the same manner as they (the missionaries) used it. However, when missionaries spoke to the Japanese of God, they used the term `Tendō`.(51)

In the `Kirishitan Ōrai` (貴理師端往来), a volume of work that compiled messages created by missionaries when proselytising to the Japanese, it stated that … `Devotion to the way of heaven by making one`s way to a temple in the morning and evening in order to pray for salvation in the afterlife is not done purely out of self-interest. This should be clearly understood, and the message taken to heart`. To ask for salvation in heaven was thus expressed using the term `Goshō wo negau` (後生を願う), while belief in God was referred to as `Tendō wo zonjitatematsuru` (天道を存じたてまつる).  Both Japanese Christians and the god of the Christians were referred to using the term `Tendō`.(52)

Amongst Sengoku daimyō, it was regular practice to exchange a `vow` (known as a Kishomon) when creating an alliance. This vow stated that all those who joined the alliance were to respect and obey their vow. If any betrayed their vow, then `Bonten (梵天), Taishaku (帝釈), Shidaitennō (四大天王), and all the great and minor gods throughout the land, Tenma Tenjin (天満天神), Atago Daigongen (愛宕大権現), and Marishi Sonten (摩利支尊天) would exact their revenge` on the perpetrator, thus making this a vow to all of the gods within Japan. On the other hand, a Christian daimyō, such as Ōmura Sumitada, in a vow sent to the Ryūzōji in the sixth month of Tenshō 4 (1576), stated that if the vow were broken, then this would be evidence of `a separation from the grace of the way of heaven, so that they were no longer blessed with martial prowess. They would atrophy, and their children and grandchildren, indeed all of their household, would meet with misfortune`.(52)

Hence Christian daimyō also referred to their god using the term `Tendō`. Christian daimyō have been thought of as having embraced a philosophy that was different to that practiced by other Sengoku daimyō, and that they were culturally separated from other daimyō. Yet the concept of `Tendō` was well-entrenched in Japanese society by the time the missionaries began using it in their sermons. This stemmed from the Confucian tradition of `the way of heaven` imported from China. In the `Nippon Shoki` (日本書記) it stated that `when politics acts in deference to the `way of heaven`, it is a sign from heaven (an indication of heaven`s blessing)` (as written out in the record for the first month of the twelfth year of the reign of the Tenmu emperor). In the Konjyaku Monogatari Shū (今昔物語集), a work written during the Heian period, it said `The way of heaven will not forgive the killing of an enemy of one`s ancestors (volumes 24 and 25, from the Taira no Koremochi Rōtō Hisatsugo (平維茂郎等被殺語), thereby showing that the concept of Tendō brought over from China had by this stage permeated aristocratic society. Indeed the term continued to be used from the Nambokuchō era through to the Edo period.(53)

An illustration of the concept of Tendō in its Confucian context can be seen in a dispute that emerged in the third year of Kakitsu (1443) between the shugo daimyō of Kaga province, the Togashi family, and Ogura no Miya, a supporter of the southern court. Rumour had it that Ogura was planning to rise up against the Togashi. However the matter ended in an internal dispute among the Togashi and the death of Ogura from illness. From the diary entry written by Fushimi no Miya Sadafusa, we learn that he was outraged at the attempt by Ogura to supplant the position of the Togashi, saying that it was an act `unforgivable to the way of heaven` (from the Kanmon Nikki (看聞日記, dated for the twenty eighth day of the second month of Kakitsu 3). Again, in a similar context, the dispute that broke out in the eighth month of Tenbun 1 (1532) between the Monto of the Honganji sect, the Rokkaku family, the Hokke sect, and the citizenry of Kyoto, which led to the destruction of Yamashina Honganji. This event was described by the aristocrat Washio Takayasu (鷲尾隆康) as `according to the way of heaven`, in that Honganji, in its excessive pride and wealth, had lost everything (from the Nisuiki (二水記), dated for the twenty fourth day of the eighth month of the first year of Tenbun). What this tells us is that the concept of `Tendō` was in general use among the population before the arrival of Christianity. Hence the concept of Tendō promoted by Christian daimyō was probably similar in kind to that held by other daimyō.(53)

Another example of the usage of `the way of heaven` lies in the instructions laid down by the founder of the (Go) Hōjō family, Hōjō Sōun, in his `Twenty-one articles of Lord Sōunji`, the content of which was laid out as follows;
「拝みをする事、身の行いなり、ただ心を直に（すぐに）やわらかにもち、正直・憲法にして、上たるをば敬い（うやまい）、下たるをば憐れみ（あわれみ）、有るをば有るとし、無きをば無きとし、有りのまゝなる心もち、仏意冥慮（みょうりょ）にも適う（かなう）と見えたり、縦い（たとい）祈らずとも、この心もちあらば、神明の加護これあるべし、祈るにも心曲がらば、天道に放され申さんと慎む（つつしむ）べし」(53-54)
There are essentially four concepts of Tendō outlined in this document. In terms of veneration of the gods and boddhisatvas, one shall `act in accordance with the thoughts and ideals of the Buddha` (仏意冥慮), one shall `ask for the protection of the gods` (神明の加護), and one shall not `deviate from the way of heaven` (天道に放され). What this tells us is that for this author, Tendō had both the power to reward and punish men, and existed as a form of `supernatural` entity. The reference to thoughts of the Buddha and protection of the gods points towards an emphasis (in the first part of the article) to belief in the gods and boddhisatva. Afterwards mention is made of concepts such as honesty and fairness (正直、憲法), and reflection of the relationship between those higher and lower on the social ladder. This emphasizes more of a secular viewpoint based on morals. The final part of the article, addressing the need for sincere prayer, demonstrates that the author, in relations with the gods and boddhisatvas, believed that faith should emphasize an internal logic, and should not rely merely on outward displays of devotion.(54)  

Warriors of this particular period believed that the `way of heaven` could dictate whether they would be successful in battle or not. It was an ideology that appeared time and again in a number of documents – the wife of Takeda Katsuyori, when the Takeda army embarked on campaign, make an offering to the god Hachiman for Katsuyori`s fate to be decided in accordance with `the way of heaven` (from the Takeda Hachiman Jinja Monjo, Tenshō 10, second month, nineteenth day). Although an army might have an advantage in numbers they could still be defeated, while another army, smaller in size than its opponent, could achieve victory. Such results were beyond the scope of human understanding, and thus all one could do was `entrust matters to the way of heaven`.(54-55) Warriors therefore placed particular emphasis on the correct interpretation of Tendō, and attempted to act in keeping with its mores. In another incident of note, Uesugi Kenshin wrote a vow which he pledged before the gods at a time when he was at war with Hōjō Ujimasa (Uesugi Ke Monjo, Tenshō 3, fourth month, twenty-fourth day). In the vow, Kenshin claimed that the Hōjō had acted illegally, and although a Kishomon had been written between Kenshin and Ujimasa as part of a truce arranged between both sides, the Hōjō had broken their promise one year after signing the Kishomon. Not only this, Ujimasa`s younger brother Uesugi Kagetora, together with his retainers Tōyama Yasumitsu and Yasuhide, had been killed under orders from Ujimasa. Ujimasa had also violated the content of his father`s, Ujiyasu`s, will, and forced his lord Ashikaga Fujiuji to commit seppuku. Hence Kenshin asked; would Ujimasa, who knew nothing of `the way of heaven` or `thoughts of the gods`, who displayed no affection towards either his parents or siblings, and who was unaware of the consequences of violating agreements, be allowed to continue without punishment from either the gods or boddhisatva? (55)

On the other hand, Kenshin vowed himself to act in accordance with Tendō, to engage in justified war, and to fulfil his religious duties.(55-56) When one examines the background to Kenshin`s thought, his belief that acting in line with the way of heaven would guarantee victory, while his opponent, because he had forsaken Tendō, was destined for defeat, reveals that the fortunes of warriors were thought to be controlled by the idea of `the way of heaven`. Yet this does not mean that Kenshin behaved in any sort of rigid moralistic way (despite the image of him as being the sole protector of `justice`, who undertook warfare reluctantly). Even for the `moralistic` Kenshin, betrayal and subterfuge produced benefits that added to his strength, and was a technique that he used in order to survive, a trait that was familiar to any common samurai or mercenary.(56)

A further example involves a letter written to one Okamoto Echigo no Kami, a warrior partaking in Hideyoshi`s invasion of the Chōsen peninsula (part of the Okamoto Ke Monjo, Okamoto Echigo no Kami Shojō). In the letter, Okamoto states that the warriors on the Japanese side were tempted with offers from the Ming army to surrender. The letter explained how the Ming had arrived to besiege the Japanese at Ulsan. They offered amnesty to any Japanese that would surrender, and would add them to their own forces. In two works on prophecy that existed in Japan at the time, the Shōtoku Taishi no Mirai Ki (聖徳太子の未来記) and the Yaba Taishi (野馬台詩), both predict that the Japanese army would be defeated, saying that `the manner in which the Japanese behaved was dictated by greed and avarice, they had betrayed both `the way of heaven` and the gods and boddhisatvas, whereas the Ming army acted with benevolence and justice, illustrating their respect for the `way of heaven` as well as the gods and boddisatva. The difference between the two forces was quite marked (literally it was like stones before eggs, and vice versa), leading to the destruction of the Japanese army `.(57) An ideology that supposed that when one`s allies (as well as oneself) acted out of respect to `the way of heaven` by being based on the mores of `the way of heaven` was all the more convincing when it turned out to be true. Leaving aside whether the above letter was genuine or not, the warriors of the age were particularly concerned with whether `the way of heaven` would favour them or not. This then explains the effectiveness of the reasoning given for `the way of heaven`, and how it could be used to justify one`s actions and the course of events.(57)

What warriors of the Sengoku age understood, and which was demonstrated through the example of Kenshin, was that a firm belief in the gods and boddhisatva was in accordance with `the way of heaven`. Any who betrayed the `way of heaven` would receive divine punishment, while those who protected it would be blessed.(57) (there follows an example of the siege of Kiyosu castle (清洲城) by the forces of the Oda. The ruler of Kiyosu castle, Shiba Yoshimune, betrayed some of his allies (together with aid from Sakai Daizen) and had them killed. It gradually became known that Yoshimune had orchestrated the attacks, an act that was considered an `audacious act of treachery`, for which Yoshimune had been duly punished. To act in this manner meant that one would lose the `way of heaven`. Hence to realize the `way of heaven`, one had to take into consideration the factors of gods and boddhisatvas.(58)

Obedience and belief in the gods and boddhisatva were indispensable to the practice of Tendō. Yet who and what were the gods and boddhisatvas that were spoken of in this way? While secular belief dictated that the entire archipelago was home to eight million gods, two of the principal gods of worship was the founder of the imperial lineage, Amaterasu Daijin, as well as (in the case of warriors) the god of war, Hachiman (Hachiman Daibōsatsu). As for boddhisatva and Buddha, the missionaries within Japan noticed that the Japanese venerated a large number of boddhisatva, centered around Shaka Nyōrai and Amida Nyōrai. It is unclear as to who specifically prayers were devoted to when invoking `gods and boddhisatvas`, yet the people of the Sengoku era widely used the term `gods and boddhisatvas` (神仏) to convey the sincerity of their beliefs.(58)

Common scholarship believes the amalgamation of ideas related to boddhisatva and native Shintō gods to place around the Heian period. The well-known theory of `Honji Suijyaku` (本地垂迹) explained that each of the gods of Japan was in fact a personification of the Buddha in that particular area or region, and that the Buddha adopted these various forms in order to be more easily comprehensible to the people of Japan. Dr Satō Hiroo, in his analysis of belief in the duality between gods and Buddha, stated that `all of the gods, in their many forms, are in essence one and the same` (佐藤弘夫氏、神国日本、ちくま新書五九一、筑摩書房、2006年、七六―七七頁). Each of the gods could therefore be venerated by worshipping just one god. Just how the members of the warrior class venerated the gods and boddhisatva is illustrated in the actions of Betsugi Dōsetsu (Akitsura), a retainer to the shugo daimyō of Bungo province, Ōtomo Sōrin. When admonishing Sōrin for his behaviour, Dōsetsu claimed that `Japan is commonly known as the land of the gods, hence it is very important not to act against morals or `the way of heaven`, whether this be related to good or evil, the relationship between a lord and his retainers, or in beliefs in general` (from the Tachibana Ke Monjo, second month, sixteenth day, Betsugi Dōsetsu Jō). Sōrin, in order to express his devotion to Christian beliefs (or Tenjikushū, or 天竺宗), proceeded to destroyed shrines and temples, cast images of the gods and boddhisatva into rivers, or else had them cut up for firewood, issuing a direct challenge to former beliefs. The concept of `the way of heaven`, if it can be said to have a second prime concept, stated that unwavering belief in and veneration of the gods and boddhisatva of Japan was in `accordance with the way of heaven`.(59) Hence when Sōrin was defeated at the battle of Mimigawa in Tenshō 6 (1578), people interpreted this loss as a sign of divine punishment for Sōrin`s having abandoned belief in the gods and boddhisatva for Christianity. If the logic of `the way of heaven` could influence one`s fortunes in war, then it is only to be expected that belief in the gods and boddhisatva was taken very seriously.(59)

It was not enough to just simply venerate the gods and boddhisatva, and act in accordance with both the will of the gods and laws. One had to make it a fundamental part of one`s character. As the twenty-one articles of Lord Sōunji stated, one should `speak one`s mind both honestly and directly`, that one should act honestly, fairly, and justly, one should display due deference and loyalty to those higher on the social scale than oneself, while showing mercy and compassion to those lower on the social scale. Such traits were considered of great importance, which one either `did or did not have`. These articles appear at first glance to have no religious significance, and are merely precepts based on secular morals. Yet as Uesugi Kenshin revealed in his vow, Hōjō Ujimasu`s behaviour in betraying his vow to Kenshin, having his brother and retainers murdered, and defying the content of his father`s will were all immoral acts to be avoided, hence moral behaviour was considered a vital factor in adhering to the `way of heaven`.(60)

Asakura Norikage (朝倉教景, also known as Sōteki, or 宗滴), an important retainer of the Asakura family of Echizen, left a record of instructions and lessons in the form of a diary known as the Asakura Sōteki Waki (朝倉宗滴話記). In this document, he stated that a betrayal of the will and lessons of one`s ancestors would be an act `against the way of heaven`. Although the repercussions of the act might not affect the person who committed them, the consequences would eventually be passed on to later generations, leading to the destruction of the household. As Norikage wrote…`The way of heaven is indeed terrible`. To act in accordance with the will of one`s ancestors was not a simple religious belief, but was an unwritten law that lay at the heart of an ideology meant to temper one`s fate in the secular world. Prof Kanda then goes on to quote an example of the punishment of `the way of heaven` that emerged from affairs between Rokkaku Yoshikata (Jōtei) and the Saitō family of Mino province (found in the 春日倬一郎氏所蔵文書、永禄三年七月二十一日六角承禎（じょうてい）条書). The example illustrates a lack of filial piety, and how this had `turned all upside down`, inviting the `end of the world`, and that one could not escape the punishment of `the way of heaven`. To make an alliance with a family whose own leader had behaved in such an abominable manner would be the end of the Rokkaku.(60-61)

For daimyō of the Sengoku era, many of whom rose to prominence through their own efforts and who therefore seemingly ignored social conventions, mores, and morals, how did they interpret what constituted moral behaviour? In other words, in order to achieve victory, did these daimyō have no choice but to abandon reason, justice, and mercy? An examination of the words and actions of daimyō of this period would suggest that the image of Sengoku daimyō as being entirely ruthless is quite far from the truth. The Rokkaku family itself worried about how they were being perceived, about their social position and the morality of their actions. In a world ruled by chaos,the Rokkaku were unable to dictate their own fate, and so were defeated by Oda Nobunaga and ceased to exist. Yet at the same time, Nobunaga himself was known to made pronouncements venerating `the way of heaven` and the need to act in a moralistic manner. Prof Kanda then quotes an example taken from the Sūfukuji Monjo (崇福寺文書、九月二十二日織田信長書状), noting Nobunaga`s own observation of the reasons for the defeat of his son Nobukatsu in battle in Iga province. According to Nobunaga, abandoning the fundamental reasoning that every military leader should possess resulted in punishment according to the `way of heaven`. He used this logic to scold his sons, a logic that was the same as that Rokkaku Yoshikata used in his criticism of his son`s behaviour. (62) Although Nobunaga himself is often described as a `revolutionary thinker`, amongst the warrior class the providence of `the way of heaven` was a high priority, and to this end Nobunaga was no different to the many other daimyō of his era.(62)

Prof Kanda then continues his narrative with an example of the concept of `the way of heaven` in the imperial household. He again takes an example from the records of Oda Nobunaga, and his decision to take a piece of the `Ranjyatai` (蘭奢待), an aromatic wood stored within Tōdaiji and an offering from the Shōmu emperor (聖武天皇). Nobunaga intended to have this wood sent as a gift to the Ōgimachi emperor (正親天皇) as a sign of his respect, however Ōgimachi was displeased with the gift, not on account of the gift itself, but the way in which Nobunaga received permission to take it (the content of Ōgimachi`s dissatisfaction was relayed in a Naijisen (内侍宣, a document written by a female attendant that conveyed the will of the emperor). The wood was a holy relic that had been donated by an emperor to Tōdaiji. If Nobunaga wanted permission to use it, he should have used an imperial messenger, and should not have employed a Chōjyasen (長者宣, a document issued by a senior member of the Fujiwara family) to convey his thoughts (as this document was associated with the Fujiwara family, whose tutelary temple, Kōfukuji, was a major rival to Tōdaiji). Such an act invited the `fury of the Shōmu emperor`, for `the way of heaven` was indeed terrifying (records of the Kyoto Gosho Higashiyama Go-Bunko Kiroku – 京都御所東山御文庫記録 for Kohyakushichi (甲百七), Shoji (諸寺), and Tōdaiji (東大寺). What this essentially meant is that Nobunaga, by ignoring the will of Ōgimachi`s ancestor the Shōmu emperor, was acting contrary to `the way of heaven` and thus committed a grave error.(63)

If an emperor feared and respected `the way of heaven`, then it was only to be expected that the same ideology would find its way into secular documents involving warriors and invoked as a form of punishment. As the `Shinchō Kōki` (信長公記) revealed, breaking an oath, acting contrary to the logic of superior and inferior, or acting against what were considered common secular morals all led to divine punishment based on the providence of `the way of heaven` (thereafter follow examples from Kiyosu castle and the battle of Okehazama).(65)

An essay written by Otogi Zōshi (御伽草子) on the origins of the practice of gathering seven types of grass on the 7th day of the 1st month, was outlined in the Nanakusa Zōshi (七草草紙). The son of an elderly couple, desperate to have his aged mother and father regain some of their youth, performed acts that assisted his prayers to `the way of heaven`. All gods and boddhisatva, taking pity on him, convinced Teishakuten (帝釈天) to descend from heaven and grant the boy his wish, saying that `those within this world that dutifully respect their parents shall be blessed by the way of heaven`. This was all very well for a person who wished to adhere to common morals, yet in the vicious world of the Sengoku era, questions of whether to conform to moral behaviour, or whether `the way of heaven` would bless one with victory or defeat were all seriously pondered.(66)