All four kanji represent centers—with slight differences. An axis (軸) lies inside something (a planet, feather, or scroll), as does marrow (髄) and a core (髄 or 芯). Other objects (e.g., doors) revolve around pivots (枢). The body contains specialized brain centers, as well as an axis, marrow, and a core. More abstractly, an axis occupies the center of one's existence. Also, one feels things to the core, the essence of an activity (e.g., aikido) is vitally important, and 枢 helps symbolize the center of the economy, of power, and more.

These four essays provide the key to happiness. With 暇 one has free time, whether a vacation, a leave of absence, or simply time to kill. Then 娯 provides destinations for having structured fun, including amusement parks, theaters, or venues for karaoke, pachinko, or horse races. With 愉 people relax into a carefree sense of fun and pleasure. And with 悦 one can experience joy and delight in a variety of things, including hospitality, a sense of progress, food, artistic masterpieces, a college acceptance, religious rapture, and sexual ecstasy.

A book title mentioned in the 霧 essay collectively refers to clouds, rain, and fog by citing their common "rain" radical. That unites the kanji in this bundle, as well. All four essays explore the realities of damp weather, as when fog grounds planes, frost damages crops, and people seek shelter from the elements. Because of such challenges, these characters make great metaphors. The Japanese associate 霜 with hardship; 曇 with life's ups and downs, as well as gloomy feelings; 霧 with mental fog; and 露 with transience. Because 露 symbolizes vanishing realities, that kanji in particular has inspired poetry.

Characters for body parts often feature 月 radicals. That's true here, but these four kanji have much more in common. First, limbs and joints are prone to soreness, injury, and disability, requiring various healing modalities. Second, the shoulders, elbows, and knees can show how we're relating to other people; the Japanese associate these body parts with lending support, sitting close for an intimate talk, and reining in someone's behavior. Those body parts also play roles in martial arts and sumo. Finally, one's stance can express seriousness, tension, pride, shame, discouragement, respect, remorse, shame, or a lack of reservedness.

Sometimes a mountain isn't just a mountain. See how the Japanese associate certain parts with the peak of a crisis or with a risky situation that leaves no room for error. Find out how most of the population reveres mountains as sacred and how they act on these beliefs. Discover a legendary rivalry between two great mountains, one that proved transformative for both. Learn how particular perceptions of mountains have inspired famous artwork. And see how, to the Japanese, the foot of a mountain appears to be the hem of its "skirt"!

The sun, moon, and seasons are natural clocks, but time is also a construct. As this bundle shows, the Japanese divide time into units of 10 (days, months, or years), also perceiving 72 microseasons. Japan has observed lunar, solar, and other calendars, plus 60-year cycles and multiple era systems. For all this precision, people approximate time with "the good old days," "once upon a time," or "around the time." They also have a particular take on time when saying that a food is in season, "at your age," and "It's a great time" for a certain activity.

Tenacity binds these essays together, sometimes as the secondary sense of characters. The literal stickiness of 粘 (e.g., natto, clay, and snail mucus!) inspired the figurative meaning "tenacity," as in "stick-to-it-ness." Mainly, 執 involves performing tasks (often by wielding long, thin objects such as pens or batons), but as "tenacity" this kanji drives words about persistence, obsession, and grudges. The whole bundle showcases adherence to beliefs and goals, doing things thoroughly, and seeing things through (e.g., athletes who accomplish greatness). These essays also depict the dark side of such devotion—namely, obstinacy, self-centeredness, discord, monomania, ill health, and more.

The 酔 essay examines intoxication from every angle, including great Osaka bars, studies of drunkards, tipsy cats and wasted elephants, and hangover prevention. The other three essays detail the processes of making saké, shochu, and beer, exploring all of the following (and much more): the ingredients in alcohol, the intricacies of fermentation, modes of distilling and brewing, malt, an old method of making saké by chewing rice and spitting it out, saké as a living entity, the image problem saké once had in Japan, alcoholic offerings to gods, the health benefits of shochu, and using alcohol to make food.

This bundle presents life at a range of speeds. Two essays focus on gradual change—for better and for worse—in everything from health to the economy. By contrast, three essays touch on sudden developments, including the outbreak of war, a surge of energy, the rapid rise of subcultures, getting an erection, standing up abruptly, bursts of wit, quick enlightenment, and sudden death. Tying these extremes together, 頓 runs the gamut; when it means "to stay in place" or "stop," this kanji involves setbacks and stalemates, but as "sudden" it pops up in words for wild, crazy behavior.

In Japanese cuisine, beautiful presentations are paramount, beginning with the pottery. Essay 1650 explains the philosophy of such aesthetics, including the Zen idea that the transformation of clay into teacups is a religion itself. The other three essays provide vocabulary that distinguishes between vessels (dishes, bowls, and cups) of different sizes and depths. Those essays explore the terms donburi, hibachi (not what you might think!), suribachi, and hachimaki. Moreover, those sources show how, from a kanji perspective, the crowns of our heads are upside-down pots or flat dishes, also explaining how one might eat a "big serving of the head"!

All who wander are not lost, at least not with this collection of kanji. They largely represent the happiest forms of aimless wandering, hedonism, freedom from worldly concerns, and wanderlust. Yes, this can veer off into extramarital affairs, restlessness, vagrancy, and unemployment. One kanji figures into a term for "failed college applicant." But another relates to essay writing as "following the pen" wherever it wishes. And two essays in this bundle touch on the Sanka, Japan's homegrown nomads and original hippies. Let freedom ring!

A waterway poses challenges to travelers, but such obstacles are surmountable, as all these kanji demonstrate. Both 越 and 渡involve crossing rivers via bridges or boats, and 越 is in a town name that actually means "crossing the river." As 沖 often pertains to fishing some distance from the shore, crossing that water reaps benefits. With 遡 one goes upstream, either along the shore on foot or in the river itself if one is a salmon looking to spawn. The carp, which famously swims upstream, symbolizes courage, spirit, and achievement for conquering the challenges of a waterway.

Bathing in Japan could mean communing with nature, following rigid procedures in a bathhouse, or soaking in water that other relatives have used. These essays cover all situations. They introduce practical terms for "bathtub," "turning on a faucet," and "overflowing." You'll learn where people bathed before owning bathtubs. You'll see how, in bathhouses, smaller, raised pools and larger pools below floor level respectively represent land and sea. You'll learn which "bathtub" term the Japanese associate with empty basins versus full pools at hot springs. And you'll discover how bathing has connected to religion, family bonds, prostitution, and a famous thief.

The Japanese have long corrugated the earth, mounding and trenching it with grand plans. Embankments (堤) rise above rivers to prevent floods. Dug-out moats (堀), whether empty or full, contrast with higher bordering land for castle defense. An agricultural field features ridges (畝) and furrows, with plants in raised areas, irrigation in "valleys." A footpath is just high enough above a flooded rice field (畔) that 畔also represents "causeway, a raised road across low or wet ground." See how the Japanese have gone to great lengths to create "corduroy" landforms.

Rock around the clock with these four kanji. They might seem to represent mere points in a 24-hour stretch. But as 午 appears in terms for "morning" and "afternoon," it applies to a large chunk of the day. Then 宵 takes over, generally meaning "early evening" but also sometimes "evening." We find 更 in terms for the ancient Chinese system of night watches that ran from about 7 p.m. to 5 a.m. Night ends with dawn (旦). These multipurpose kanji also symbolize parts of the year, from New Year's (旦) to late autumn (更).

These essays detail complex, interdependent systems, both natural and economic. Sericulture was once so essential to Japan's economy that mulberry (桑) fields are marked on maps, as silkworms eat only mulberry leaves. These animals laboriously spin cocoons (繭), producing filaments that become silk kimonos after many financial transactions. Similarly, Japanese apiarists oversee busy bees (蜂) that make not only hives and honeycomb but also honey to be sold and consumed in multiple ways. Animals build intricate nests and webs (both 巣) that inspire terrific Japanese figurative language. People even eat some nests!