What flows

Phonetic-semantic compound with poetic etymology: 氵 (water) + 每 (originally derived from 母, mother — providing both phonetic value and semantic suggestion). The encoded image: "the great water that, like a mother, receives all rivers". 海 sits at the largest end of the CJK water-size hierarchy: 川 (small stream) → 河 (river) → 江 (great river) → 海 (sea / ocean). Identical across 繁體 / 新字体 / 简体.

Mandarin: hǎi, dipping 3rd tone. 海 anchors maritime vocabulary: 海洋 (hǎiyáng, ocean), 海岸 (hǎi'àn, coast), 海军 (hǎijūn, navy), 海鲜 (hǎixiān, seafood — "sea-fresh"), 海带 (hǎidài, kelp), 海归 (hǎiguī, "sea-returner" — Chinese students who studied abroad and came back). The city 上海 (Shànghǎi) literally means "above-sea / by the sea". The Yellow Sea (黄海) and East China Sea (东海) define China's eastern boundary.

Japanese: on-reading カイ (kai) for compounds — 海洋 (kaiyō, ocean), 航海 (kōkai, voyage), 海軍 (kaigun, navy), 海岸 (kaigan, coast). Kun-reading うみ (umi) is the everyday word — 海 (umi, sea), 海辺 (umibe, seaside), 海鳥 (umidori, sea bird). Japan, surrounded by sea, deploys 海 vocabulary heavily — 海女 (ama, female pearl divers, an iconic Japanese cultural tradition), 海苔 (nori, seaweed sheets — for sushi), 海老 (ebi, shrimp/lobster — irregular reading meaning "sea-old").

Note 北海道 (Hokkaidō) — Japan's northernmost prefecture — combines 北 + 海 + 道, literally "Northern Sea Road".

Memory aid: water + mother — the great water that receives every river.

Phonetic-semantic compound: 氵 (water-radical) + 由 (a phonetic). The encoded meaning: "the liquid that flows like water but isn't water" → oil. To ancient observers, oil was a "kind of water" that pours and flows, hence the water radical. Identical across 繁體 / 新字体 / 简体.

Mandarin: yóu, rising 2nd tone. 油 covers cooking oil, petroleum, paint, and slick textures: 石油 (shíyóu, petroleum — "stone oil"), 汽油 (qìyóu, gasoline — "vapor oil"), 食用油 (shíyòngyóu, edible oil), 酱油 (jiàngyóu, soy sauce — note: not actually oily, but called "sauce oil"), 油画 (yóuhuà, oil painting), 加油 (jiāyóu, add oil — both literal "fill the gas tank" and figurative "go for it / cheer up!"). The slang 加油! (jiāyóu) is the most-shouted Chinese sports cheer, equivalent to "Go! Go!" in English.

Japanese: on-reading ユ (yu) — 石油 (sekiyu, petroleum), 灯油 (tōyu, kerosene / heating oil — used for the kerosene heaters common in Japanese homes), 給油 (kyūyu, refuel), 醤油 (shōyu, soy sauce — note: same compound 醤油 as Mandarin 酱油, though Mandarin uses different reading). Kun-reading あぶら (abura) is the everyday word — 油 (abura, oil), ごま油 (gomaabura, sesame oil), サラダ油 (sarada-abura, salad oil), 油っこい (aburakkoi, greasy / oily — used for food).

醤油 (shōyu, soy sauce) — Japan's essential condiment — uses this character. The Cantonese romanization "soy" (from 醤 = sauce + 油 = oil) is what gave English the word "soy" in "soy sauce" / "soybean".

Mandarin's 加油! (jiāyóu) — literally "add oil" — has even entered English dictionaries (Oxford added "add oil" as an entry in 2018) due to widespread usage among Hong Kong English speakers.

Memory aid: water that flows differently — oil as a "second water".

池 is a phono-semantic character: 水 (氵, water) carries the meaning, 也 lends the sound. Water that gathers and stays in one place — a pond or pool. 也 only lends the sound "chí/ji"; it has nothing to do with the meaning.

Mandarin: chí, 2nd tone. 池塘 (chítáng, pond), 游泳池 (yóuyǒngchí, swimming pool), 电池 (diànchí, battery), 水池 (shuǐchí, basin). The word 电池 (battery) is vivid — electricity in a "gathering pool."

Japanese: on-reading チ (chi), kun いけ (ike). 池 (ike, pond), 電池 (denchi, battery), 貯水池 (chosuichi, reservoir), 古池 (furuike, old pond) — from Bashō's famous haiku "the old pond, a frog jumps in, the sound of water." The pond is a central element of the Japanese garden.

Korean hanja-sound "ji": 貯水池 (jeosuji, reservoir), 電池 (jeonji, battery), 天池 (Cheonji, the crater lake atop Mount Baekdu), 蓮池 (yeonji, lotus pond).

Memory aid: water (氵) that gathers and stays — water collected in one place rather than flowing away.

汽 is a phono-semantic character: 水 (氵, water) carries the meaning, 气 (vapor) lends the sound. Water (氵) rising as vapor (气) — steam. 气 was originally the shape of rising air or mist, and here it serves as both sound and sense.

Korean hanja-sound "gi": 汽車 (gicha, train), 汽船 (giseon, steamship), 汽笛 (gijeok, the whistle of a train or ship), 蒸汽 (jeunggi, steam). The word 汽車 (train) came from the steam locomotive that ran puffing out vapor.

Mandarin: qì, 4th tone. 蒸汽 (zhēngqì, steam), 汽车 (qìchē, automobile — "the vapor-driven vehicle"), 汽油 (qìyóu, gasoline), 汽水 (qìshuǐ, soda / pop). Intriguingly the same word 汽車 means "automobile" in Mandarin (qìchē) but "train (steam locomotive)" in Japanese and Korean.

Japanese: on-reading キ (ki) — there is no kun-reading (this is an on-only character). 汽車 (kisha, steam locomotive), 汽船 (kisen, steamship), 汽笛 (kiteki, steam whistle). Japanese 汽車 (kisha) refers to the old steam train; today's electric trains are distinguished as 電車 (densha).

Memory aid: water (氵) rising as vapor (气) — the steam that surges from boiling water.

Three parallel flowing strokes. If 山 is three peaks, 川 is three streams. The earliest oracle bone forms were curvier, capturing the motion of water itself; later scribes straightened the curves into the three vertical lines you see today. Identical across 繁體 / 新字体 / 简体.

The character sits inside a small family of CJK water-words ranked roughly by size: 川 (small stream), 河 (river — most general), 江 (large river — historically the Yangtze specifically), 海 (sea). Native speakers feel the size difference even though English collapses everything to "river".

Mandarin: chuān, level 1st tone. The province 四川 (Sìchuān, "four rivers") is named for its four major waterways draining the basin. The idiom 川流不息 (chuānliú bùxī, "flowing without stopping") describes ceaseless traffic — picture continuous rush-hour cars as a river.

Japanese: on-reading セン (sen) appears in 河川 (kasen, rivers/waterways). The kun-reading かわ (kawa) is far more common — and is one of the most frequent components in Japanese surnames: 川田 (Kawada), 川上 (Kawakami, "upriver"), 川下 (Kawashimo, "downriver"), 中川 (Nakagawa, "middle of the river"), 小川 (Ogawa, "small stream").

Memory aid: three straight vertical strokes. Peaks for 山, streams for 川.

水 pictures water itself — a central flowing stroke flanked by splashing droplets. Where 川 is the riverbed, 水 is the substance. Identical across 繁體 / 新字体 / 简体. The most important radical-shape transformation in the entire script lives here: when 水 appears on the left of a compound character, it becomes 氵 (the "three-dot water" radical). Once you see 氵 you can predict the meaning involves water — 江 (river), 海 (sea), 湖 (lake), 泳 (swim), 汁 (juice), 浴 (bathe), 汚 (dirty/polluted). It is the single highest-yield radical to memorize early.

Mandarin: shuǐ, dipping 3rd tone — the pitch contour itself sounds like a small splash. 水果 (shuǐguǒ, fruit — literally "water-fruit"), 喝水 (hē shuǐ, to drink water), 风水 (fēngshuǐ, "wind-water" — the geomancy system Western readers know as feng shui), 矿泉水 (kuàngquánshuǐ, mineral water).

Japanese: on-reading スイ (sui) in Sino-Japanese compounds — 水曜日 (suiyōbi, Wednesday), 水泳 (suiei, swimming), 水準 (suijun, standard/level). The kun-reading みず (mizu) is the everyday word — 水 (mizu, water), 飲み水 (nomimizu, drinking water), 水着 (mizugi, swimsuit). Note that Wednesday is "water day" in the East Asian planetary week.

Memory aid: a vertical center stroke with two pairs of droplets falling outward — the picture is the meaning.