Lips touching lips. The simplest mechanical event in the catalogue of physical affection. Anthropology has spent a century discovering that the apparent universality of this act is, in fact, distinctly cultural.

Overview

Seppun (Japanese: 接吻, seppun) is the formal Japanese term for kiss, the act of pressing the lips against another person’s lips, face, hand, foot, or other part of the body. The Japanese register includes the formal seppun, the loanword kisu (キス), and the more literary kuchizuke (口づけ, “mouth-pressing”). English distinguishes the act itself (kiss) from the type of kiss (French kiss, peck, open-mouth kiss) and from the verbal-noun form (kissing).

The act covers an extraordinary range of social meanings. The kiss a mother gives her sleeping child, the kiss exchanged at a wedding, the kiss of peace exchanged in a Catholic mass, the kiss between lovers, and the kiss to the ring of a religious dignitary all involve the same elementary physical gesture but operate as completely different social signals. The semantic context-dependence of the kiss is part of what has made it a recurring subject across anthropology, semiotics, and psychology.

This article focuses on the kiss as a sexual and affectionate act, treating its physiology, anthropological distribution, Japanese cultural reception, and twentieth-century media history. The deeper-form sub-category that involves the tongue is the French kiss (Japanese: ディープキス, diipu-kisu).

Etymology

The Japanese word seppun (接吻) is a two-character compound: 接 (touch, join, meet) + 吻 (mouth, beak), literally “to bring lips into contact”. The term was coined in the Meiji period as a translation of European kiss/Kuss/baiser vocabulary, when the act became conceptually distinct from the wider Japanese repertoire of lip-related expressions (which had previously used kuchi-sui, “mouth-sucking”, and the shunga euphemism ro no ji, “the character 呂”). The two-character compound captures the act in a deliberately neutral and physical-descriptive register.

The English kiss derives from Old English cyssan and Proto-Germanic *kussjan-, with onomatopoeic Proto-Indo-European roots. Classical Latin maintained a more differentiated vocabulary: osculum (the ritualised, respect-and-affection kiss), basium (the affectionate kiss), and suavium (the sensual, sexual kiss). The Latin distinction shows that ancient cultures often disaggregated what modern languages have re-collapsed into the single concept kiss.

Physiology

Neuroscience

The lips are among the densest concentrations of touch receptors in the human body. On the Penfield somatosensory cortical map, the lips occupy a notably enlarged region alongside the fingers and tongue, reflecting their disproportionate representation in the brain. Kissing is therefore, by sensory-density metric, among the most informationally rich forms of body contact available between two humans.

The neuroendocrine response to kissing involves multiple regulatory systems. Oxytocin (the bonding hormone), dopamine (the reward-system neurotransmitter), serotonin, and endorphins are all involved in the response to extended kissing, and the combination is widely understood to contribute to pair-bond formation, emotional connection, and stress reduction. Sheril Kirshenbaum’s The Science of Kissing (2011) provides a popular-science treatment of the physiological substrate.

The MHC-assessment hypothesis

Evolutionary biology and behavioural ecology have proposed that kissing functions as a mechanism for evaluating mate compatibility through olfactory and gustatory cues. The Major Histocompatibility Complex (MHC), the immune-system gene cluster, varies between individuals, and humans (like other vertebrates) appear to prefer mates with MHC profiles different from their own. Claus Wedekind and colleagues’ classic 1995 sweaty-T-shirt experiment showed that women rated body odour from men with different MHC profiles as more attractive.

Kissing exposes two people to one another’s salivary and breath chemistry at very close range, which could in principle convey MHC-related information. The hypothesis that kissing functions in part as MHC assessment remains speculative; the evidence supporting it is suggestive rather than definitive.

Saliva exchange

Open-mouth kissing involves the transfer of saliva between participants. A widely cited estimate (sometimes overstated in popular media) is that ten seconds of open-mouth kissing transfer approximately 80 million bacteria. The microbial-flora exchange may have immune-system implications, though this remains a hypothesis rather than a confirmed mechanism.

Anthropology

Is the kiss universal?

The romantic-sexual kiss has long been assumed to be a human universal. Twenty-first-century anthropological work has substantially undermined this assumption. The most cited recent study is Jankowiak, Volsche, and Garcia’s 2015 survey of 168 cultures, which documented romantic-sexual kissing in only 46 per cent. The remaining 54 per cent either do not practise romantic-sexual kissing or do not have it as a culturally established form.

Cultures in which romantic-sexual kissing is absent or rare include parts of sub-Saharan Africa (particularly some hunter-gatherer societies), the Amazon basin Indigenous peoples, parts of highland New Guinea, and several Pacific island societies. In some of these cultures, mouth-to-mouth contact is regarded as unhygienic or even repugnant, and the role that lip kissing plays in Western romantic encounters is filled by smelling, licking, cheek-rubbing, or nose-rubbing alternatives.

This finding has had a substantive impact on the literature. It indicates that romantic-sexual kissing is a cultural rather than biological practice, and that the European-derived assumption of its naturalness reflects cultural ethnocentrism rather than human universality.

Origin hypotheses

Several non-exclusive hypotheses have been proposed for the evolutionary origin of kissing.

The premastication hypothesis derives kissing from the practice of mothers chewing food and transferring it mouth-to-mouth to weaning infants. The act of pre-chewing food for a young child involves close lip-to-lip contact and produces sustained close-range mother-infant interaction.

The olfactory grooming hypothesis derives kissing from close-range smelling and breath-sensing as a form of social grooming. The exchange of body-chemistry information between intimates is shared across many primate and other mammalian species and would have provided a natural substrate for the evolution of human kissing.

The primate lip-contact hypothesis derives human kissing from the lip-touching behaviours observed in bonobos and chimpanzees, particularly during the post-conflict reconciliation behaviour bonobos display.

None of these is definitively established; the evolutionary origin of kissing remains an open research question.

Westermarck’s classic observation

Edward Westermarck’s History of Human Marriage (1891) is the classic early anthropological reference recording that romantic kissing is not universal. Westermarck surveyed the ethnographic literature of his time and documented cultures using nose-rubbing (the Eskimo kiss, more accurately a Greenlandic Inuit practice), smelling, and breath-blowing alternatives, raising the substantive question of whether the European kiss represented a cultural rather than biological behaviour.

Japanese reception

Pre-modern Japan

Mouth-to-mouth contact appears in Japanese cultural records from the earliest periods. The Kojiki (712) and Nihon Shoki (720) contain mythological references suggesting deity-figures’ mouth exchanges. Heian-period (794-1185) literature, including the Tale of Genji and the Tales of Ise, contains scattered references to lip-related expressions of intimacy. Edo-period shunga (woodblock erotic prints) frequently depict mouth-to-mouth contact between lovers, in the work of Moronobu, Harunobu, Hokusai, and Utamaro among many others.

Through the pre-modern period, however, lip kissing in Japan was strictly a private, bedroom-context act. It did not function in public, social, greeting, or ceremonial contexts, in marked contrast to the European tradition where ceremonial kisses (the pax in Christian liturgy, the loyalty kiss to a sovereign, the social-greeting kiss to the hand) were established public practices. The European concept of the kiss as a social signal simply did not exist in pre-modern Japan; the kiss as a private intimate act did, but it was contained to the private sphere.

Meiji-period adoption

The Meiji-period adoption of Western culture brought the public European kiss to Japanese awareness, but its uptake in daily life was limited. The neologism seppun was established as the translation, and intellectual-class familiarity with the European concept grew, but the social practice of public kissing remained largely outside Japanese norms. A telling indicator: when Auguste Rodin’s sculpture The Kiss (Le Baiser) was exhibited in Tokyo’s Ueno Park in 1929, public-decency objections led to its display being temporarily restricted.

Tanizaki and modern Japanese literature

Junichiro Tanizaki (1886-1965) is one of the modernist Japanese writers most associated with sustained lip-and-mouth thematic work. In Praise of Shadows (1933) does not address kissing directly but registers, through its meditation on Japanese versus Western sensibility, the cultural distance Japan was negotiating with European bodily practices. Tanizaki’s novels (Some Prefer Nettles, The Tale of Shunkin) include direct kiss scenes that operate within the Japanese modernist project of working through the country’s evolving relationship with Western intimacy norms.

Postwar normalisation

The post-1945 period, under Allied Occupation and through the inflow of American culture, normalised the public European-style kiss in Japan. The film industry’s adoption of the kiss scene (discussed below) was a key indicator and accelerator of the shift, and through the 1950s and 60s the public kiss progressively entered the Japanese everyday repertoire of affection display.

Cinema and the breakthrough of the public kiss in Japan

International precedent

The first kiss in cinema history is conventionally identified as the 1896 Thomas Edison Company short film The May Irwin Kiss (also known simply as The Kiss), directed by William Heise. The 18-second film, consisting only of a kiss between actor John Rice and actress May Irwin, was immediately controversial and remains the starting point of discussion about kissing on screen.

The 1946 Japanese breakthrough

Wartime Japanese cinema censorship effectively prohibited kiss scenes. The post-war Occupation’s cultural-liberalisation programme dismantled this restriction, and on 23 May 1946 Shochiku released Hatachi no Seishun (Twenty-Year-Old Youth, directed by Yasushi Sasaki), which is conventionally cited as the first Japanese film with an on-screen kiss scene. The kiss between Shirō Ōsaka and Michiko Ikuno generated substantial public discussion and extensive press coverage at the time.

The Daiei film Aru Yo no Seppun (A Certain Night’s Kiss, directed by Yasuki Chiba), released on the same date or in close proximity, also contains a kiss scene, and the precedence question between the two films is a matter of continuing film-historical discussion.

Whichever film holds the precedence claim, the rapid arrival of the kiss in Japanese cinema (only nine months after Japan’s surrender) symbolises the rapidity of the wider post-war reorganisation of Japanese bodily and intimacy norms.

Subsequent development

The acceptance of the kiss scene was the opening step in a multi-decade expansion of body and intimacy representation in Japanese film and television. The 1950s youth-film genre, the 1960s pinku eiga, the 1971-onward Nikkatsu Roman Porno cycle, and the adult-video industry that emerged from the late 1970s all built on the foundation that the 1946 break had established.

Variants

The kiss has substantial structural variation organised along several axes.

Body part

Lip-to-lip kissing is the central form; kissing also extends to the cheek (the common European-greeting form), forehead (parental-protective), hand (European court etiquette), neck and clavicle (sexual context), and intimate body parts (as preliminary to oral-genital contact such as fellatio or cunnilingus).

Form

Closed-mouth kissing is the most basic form. Open-mouth kissing without the tongue is a recognised intermediate form. Tongue-engaged kissing is the French kiss or deep kiss. The variant in which saliva is transferred mouth-to-mouth, sometimes called tsuba-nomi in Japanese sexual vocabulary, is a specialised form. Lip-sucking and gentle biting are further specialised variants.

Cultural form

Specific cultural forms include the Eskimo nose-rub, the Hungarian two-cheek greeting kiss, the French two- or three-cheek greeting, and the Catholic kiss of peace (pax) in liturgical practice.

Cultural and artistic reception

The kiss has been the subject of major works across the visual and literary arts. Gustav Klimt’s The Kiss (1907-1908), Rodin’s Le Baiser (1882), Robert Doisneau’s photograph Le baiser de l’hôtel de ville (1950), and many other canonical artworks have taken the kiss as their central subject.

In contemporary Japanese subculture, the kiss is a key visual signal. Shoujo manga uses first kiss scenes as narrative pivot points; adult manga and adult video use deep kissing as a central foreplay component; yuri and BL genre often treat a kiss scene as the dramatic culmination of a relationship arc, sometimes carrying the narrative weight that more explicit content would carry in other genres.

See also

• Kuchibiru
• Shita
• Daeki
• Deep kiss
• Fera