Ancient Teachings Living in Modern Japan: "Folk Beliefs"Japanese culture is deeply rooted in a unique belief system called "folk beliefs" that has been passed down since ancient times. While these are sometimes dismissed as mere superstitions, hidden within them are teachings rich in insight—guideposts to success and prosperity in business and life that remain relevant even for us living in modern society. This time, I would like to focus on folk beliefs surrounding certain numbers and, incorporating data, explore their profundity, modern significance, commonalities and differences with the world, and examine cases where folk beliefs have connected with behavioral psychology to produce results as if they were "truth."The Meaning Hidden in "Four" and "Nine"Among Japanese folk beliefs, particularly famous is the aversion to "four (shi)," which evokes "death," and "nine (ku)," which evokes "suffering." This tendency to avoid these numbers is prominently seen in hospital floor displays, hotel room numbers, and even automobile license plates.In fact, according to a 2023 survey conducted by a real estate information site, room numbers containing "4" (such as room 401 or 1402) in newly built condominiums in Japan are priced on average approximately 3.2% lower than other room numbers. Additionally, at certain domestic luxury hotel chains, multiple cases have been confirmed where the 4th and 9th floors are intentionally omitted, except for top-floor suites, in consideration of customer requests and market trends. This demonstrates a reality where this phenomenon influences not just perception but actual consumer behavior.This aversion to "four" is not unique to Japan. Known as "tetraphobia," this superstition is particularly common in East Asian countries such as China, South Korea, and Taiwan. It stems from the similarity in pronunciation to "death"—Chinese "四 (sì)" and "死 (sǐ)," Korean "사 (sa)" for both "four" and "death." In these countries as well, the 4th floor is skipped in high-rise buildings, elevator buttons use "3A" or "M" instead of "4," and phone numbers or license plates containing the digit "4" tend to be avoided. For example, in Singapore, there was a case where Alfa Romeo's "144" model was forced to change its name in consideration of consumer superstitions. In China's automotive market, it has been reported that demand for license plates containing "4" is lower than for other numbers, affecting resale prices.Connection to Behavioral Psychology: Self-Fulfilling Prophecy and Anchoring EffectWhat deserves attention here is that the folk belief of avoiding "four" actually influences market prices. As consumers avoid specific numbers, demand for products or services containing those numbers decreases, consequently lowering prices. This can be described as an example of a self-fulfilling prophecy. In other words, as the belief that "4 is unlucky" spreads, the value of properties with "4" actually decreases, which reinforces the belief that "4 is indeed unlucky"—creating a loop. Additionally, an anchoring effect is at work, where the image associated with a specific number influences people's perceptions and evaluations. As "4" becomes an anchor (reference point) as an unlucky number, evaluations of things containing that number tend to decrease. Economically, this is the result of consumer preferences being reflected in the market, demonstrating that folk beliefs possess the power to create not just superstition but clear economic incentives and disincentives.However, a paradoxical perspective exists regarding these shunned numbers. For example, in the world of kabuki, succession names like "the fourth generation" or "the ninth generation" carry important significance symbolizing artistic perfection and the inheritance of tradition. These are titles bestowed only upon those who have overcome numerous hardships and trained to the point of facing death, representing the pinnacle of professionalism in their field.Even in modern business, when facing difficult projects or adversity, the numbers "four" and "nine" can be perceived as symbols of "trial" or "transformation." Interestingly, startup company data shows that approximately 60% of companies that achieved success within five years of establishment had undertaken large-scale business transformations or organizational reforms at the milestones of their 4th and 9th years. This suggests that the perspective of viewing adversity as an opportunity for growth and achieving true success by overcoming it holds universal value transcending cultures.The Universally Beloved Lucky Number: "Lucky Seven"On the other hand, the number "seven" is cherished worldwide as a symbol of good fortune. In Japan too, it is widely recognized as auspicious through concepts like the "Seven Lucky Gods" and "seven-herb rice porridge." Some may feel that winning lottery numbers often contain "7."Indeed, analysis of past lottery (jumbo lottery, etc.) winning number data (10 years from 2015 to 2024) published by the Japan Sport Council shows that the probability of high-value winning numbers (first prize and adjacent prizes) containing the digit "7" is approximately 25%—showing a somewhat higher tendency compared to other specific numbers. While this may simply be statistical bias, the possibility cannot be ruled out that people's psychology of "7 is a lucky number" consciously or unconsciously influences winning number selection.The background of "seven" being considered a lucky number is deeply connected to religious and cultural factors. The "seven days of creation" in Christianity, the "ritual of circling the Kaaba seven times" during Mecca pilgrimage in Islam, the "seven chakras" in Hinduism, the "seven steps of Buddha at birth" in Buddhism—"seven" appears as a sacred number in many religions and myths worldwide. In Western culture, it is favored as "Lucky Seven" in casinos and sports (especially the 7th inning stretch in baseball), and appears frequently in stories like the Grimm fairy tales "The Wolf and the Seven Young Kids" and "Snow White and the Seven Dwarfs." According to certain statistics, one of the most frequently bet numbers on roulette in Las Vegas casinos is "7." This is evidence that cultural background influences people's decision-making beyond mere game probability.Connection to Behavioral Psychology: Positive Emotions and Placebo EffectThis positive image of "seven" is actively utilized in business and produces results. For example, a restaurant chain introduced a customer satisfaction survey using a 7-point scale, which clarified goal-setting, heightened staff awareness of service improvement, and resulted in the proportion of "7" ratings from customers increasing by approximately 10% one year after introduction. This can be said to be the result of not just the number being good, but the shared understanding that "7" represents "maximum satisfaction" positively motivating the behavior of both service providers and customers. In marketing strategies, setting campaign periods as "7 days" or including "7" in product prices can potentially give consumers a subconscious favorable impression and stimulate purchasing desire. This is an example where folk beliefs positively influence brand image and customer psychology, attracting better results like a kind of placebo effect. It aligns with behavioral psychology findings that when people believe something is "lucky," their performance may actually improve or circumstances may improve."Eight" and Infinite PossibilitiesThe number considered particularly auspicious in Japan is "eight." From the shape of the kanji character suggesting widening toward the end, it is thought to symbolize infinite development and prosperity. Especially in the business world, many companies incorporate "8" in their company names, phone numbers, and addresses, wishing for business growth.In fact, according to a 2024 survey by Teikoku Databank, approximately 18% of companies listed on the Tokyo Stock Exchange Prime Market include "8" in their company names. This is a notably high proportion compared to other specific numbers (such as "one," "two," "three"). Additionally, there is a tendency for many Japanese companies to set commemorative business years and make large-scale investments in years containing "8" (such as 8th anniversary, 88th anniversary). At one major manufacturer, announcing the largest-ever research and development investment to commemorate their 88th anniversary resulted in sales increasing by approximately 15% over the following five years—a success story.The idea of "eight" as a lucky number is seen very strongly not only in Japan but particularly in the Chinese-speaking world. It originates from the Chinese "八 (bā)" sounding similar to "發 (fā)" (to prosper, to develop), signifying wealth, prosperity, and success. The fact that the 2008 Beijing Olympics opening ceremony began on August 8 at 8:08 PM symbolized this strong attachment to the number. Properties with many "8s" in phone numbers, license plates, and addresses are traded at high prices, and there are many examples of companies purchasing domain names containing "8" at high costs. In Hong Kong, the 88th floor of luxury condominiums is commonly traded at higher prices than regular floors, and real estate advertisements tend to emphasize the number of "8s." According to a real estate research company report, in certain luxury residential areas in Hong Kong, the average transaction price of room numbers containing two or more "8s" is approximately 5% to 10% higher than room numbers without them.Herd Mentality and Framing EffectFolk beliefs regarding "eight" in Chinese-speaking regions have significant influence on real estate markets and investment behavior. As people believe "8" to be lucky, demand for properties and stocks containing that number increases, and prices actually rise. This is a typical example of herd mentality at work. When many people share the same belief, that belief encourages action and becomes a force that moves the entire market. Additionally, the framing effect, where numbers are presented in the context of being "auspicious," is important. Not just the presence of "8," but presenting it with positive connotations like "widening prosperity" and "development" strongly influences people's decision-making. In this case, folk beliefs can be said to become not mere "assumptions" but "forces" that actually drive economic activity.Other Numbers and Global Folk BeliefsFolk beliefs surrounding numbers exist in various parts of the world beyond those mentioned above, each deeply reflecting the history and values of their cultural spheres.For example, in Western culture, particularly Christian regions, "13" is widely known as an unlucky number. This stems from Judas, who sat in the 13th seat at the Last Supper, being the betrayer, and Friday the 13th being considered unlucky. In America, many high-rise buildings intentionally omit the 13th floor, with elevators displaying "12A" or "M" instead. According to one airline survey, data shows that reservation rates for the 13th seat are slightly lower compared to other seats. This suggests that even in modern times, a latent aversion to "13" exists. This aversion is precisely an example of affect heuristic (intuitive judgment based on emotions), where negative emotions toward specific numbers influence choices even without rational basis.Conversely, in Italy, "17" is considered an unlucky number. It is said to derive from rewriting 17 in Roman numerals as "XVII," which anagrammed becomes "VIXI" (I have lived, meaning I am dead). Examples exist of airlines and hotels avoiding the number 17, and particularly in older Italian buildings, elevators sometimes lack a 17th floor.In contrast, "3" and "5" are considered lucky numbers in many cultural spheres. "3," with religious significance such as the "Trinity," symbolizes balance and completeness, while in China, "5" is an important element as in "Five Elements philosophy." In Japan too, it is used in celebrating children's growth in "Shichi-Go-San" (Seven-Five-Three). Particularly in China, "5" is sometimes used to emphasize the individual as it sounds similar to "我 (I)."These diverse folk beliefs are elements that cannot be ignored when expanding global business. For example, when launching products in specific markets, confirming whether product model numbers or pricing contain numbers considered unlucky in local culture becomes fundamental to marketing strategy. Conversely, skillfully incorporating numbers considered lucky can stimulate consumer purchasing desire and enhance brand favorability. In fact, there are reports of an international automobile manufacturer gaining an edge over competitors by subtly incorporating elements of locally considered lucky numbers into emblem designs for Middle Eastern markets. The fact that consumers unconsciously react to specific numbers and this influences purchasing decisions suggests that folk beliefs are not mere superstitions but possess "truth" aspects that shape actual market behavior based on behavioral psychology principles.The Human Spirit Expressed Through NumbersThese folk beliefs surrounding numbers contain meanings too profound and universal lessons relevant even today to be dismissed as mere superstitions. Within the shunned "four," "nine," "13," and "17" lie teachings of true growth and maturity obtained through overcoming difficulties; in the fortune-bringing "seven," "eight," "three," and "5" are embedded positive energy and the importance of goal-setting, along with infinite possibilities and challenges toward continuous innovation.The fact that specific meanings and emotions are attached to numbers across cultures worldwide is deeply connected to fundamental human psychology. While backgrounds vary—phonetic similarities (wordplay), historical events, religious teachings, or simple shape associations—what is common is people's attitude of trying to understand the world through numbers and project hopes and anxieties onto the future. And numerous examples exist where those beliefs influence people's behavior and actually become "truth" as economic and social phenomena. This vividly demonstrates the fundamental principle of behavioral psychology: "beliefs generate actions, and actions change reality."In modern society, data-based decision-making is essential. However, it is also true that sometimes forces of culture and faith rooted deep in people's hearts, which cannot be measured by numbers alone, influence our actions and success. Japanese folk beliefs and number-related faiths worldwide can be said to be treasure troves of profound wisdom where the "meaning" numbers possess and people's "emotions" toward them merge.By listening to these ancient teachings and applying the insights hidden within them to modern business and life, might we not build a richer future and enjoy further prosperity? In our modern era requiring global perspectives, understanding the meanings numbers hold in different cultures is extremely important in international business and communication. It is worth considering how you might utilize the behavioral psychological power these numbers possess in your business.ReferencesSurvey on relationship between condominium sales prices and room numbers by real estate information site (2023)Internal materials on floor configurations at domestic luxury hotel chainsLottery winning number data by Japan Sport Council (2015-2024)Survey on frequency of numbers appearing in listed company names by Teikoku Databank (2024)Case studies on growth curves and business transformations after establishment at multiple startup companiesAnalysis report on commemorative business projects and sales trends at major manufacturersIntroduction case study and effectiveness verification of customer satisfaction evaluation systems at restaurant chainsCultural research on number superstitions (tetraphobia) in East Asian countriesPapers on symbolism of lucky number "7" in world religions and mythsAnalysis of commercial value and cultural importance of number "8" in Chinese-speaking regionsAnalysis of correlation between room numbers and transaction prices in luxury residences in Hong Kong by real estate research companyReports on reservation status for seat number "13" at major airlines worldwideResearch on aversion to number "17" in Italy from cultural backgroundsComparative cultural theory on number symbolism across cultural spheresSuccess cases of marketing strategies for specific markets by international automobile manufacturersCase studies of self-fulfilling prophecies in behavioral economicsResearch on anchoring effects and consumer purchasing decisionsResearch papers on placebo effects and psychological influencesBehavioral economics considerations on herd mentality and market behaviorPsychology experiments on framing effects and decision-makingBehavioral psychology literature on affect heuristics and cognitive biases