河口 in 30 Seconds
- 河口 (kakou) means 'river mouth' or 'estuary,' the point where a river meets a larger body of water like the sea.
- It is composed of the kanji for 'river' (河) and 'mouth' (口), making it easy to remember visually.
- The word is commonly used in geography, weather reports, fishing, and environmental science contexts across Japan.
- Key associations include brackish water (汽水域), deltas (三角州), and tidal influences, making it a B1-level essential word.
The Japanese word 河口 (kakou) refers to the specific geographical point where a river meets a larger body of water, such as an ocean, sea, or lake. In English, this is most commonly translated as 'river mouth' or 'estuary.' Understanding this word requires looking at its components: 河 (ka), meaning 'river' (typically a large or significant one), and 口 (kou/kuchi), meaning 'mouth' or 'opening.' This logical combination creates a clear mental image of the river's exit point. In daily Japanese life, this term isn't just for geography textbooks; it is frequently used in weather reports, fishing circles, and environmental discussions. For instance, when a typhoon approaches, the news might warn about rising water levels at the 河口 due to the combination of heavy rain and high tides.
- Geographical Context
- In geography, the kakou is characterized by the mixing of fresh and salt water, creating a unique brackish environment known as 汽水域 (kisuiki). This area is often rich in biodiversity, making it a focal point for ecological studies in Japan.
- Social Context
- Historically, many major Japanese cities, like Osaka and Tokyo, developed around river mouths because they provided natural harbors for trade and transportation. Thus, the word often carries a nuance of being a gateway between the inland and the sea.
その大きな川は、広い河口を通って海に流れ込んでいます。
(That large river flows into the sea through a wide river mouth.)
The word is predominantly a formal, technical, or descriptive noun. While you might use the simpler 'kawa no kuchi' (river's mouth) in very casual conversation with children, 河口 is the standard term for adults. It appears in names of famous landmarks, such as the town of Fujikawaguchiko, located near the 'mouth' of the river flowing into Lake Kawaguchi. Scientifically, the kakou is where sedimentation occurs, forming deltas (三角州 - sankakusu). Because of this, the term is essential for anyone interested in the natural landscape of Japan, a country defined by its numerous short, fast-flowing rivers that rush toward their respective 河口.
Using 河口 (kakou) correctly involves understanding its role as a spatial noun. It often pairs with particles like に (at/to), で (at/in), and の (possessive/attributive). Because it represents a transition point, verbs related to movement, accumulation, and transformation are common companions. For example, 'reaching the river mouth' is 河口に達する, and 'widening at the mouth' is 河口で広がる. In environmental science contexts, you might hear about 'the ecology of the river mouth' (河口の生態系). It is important to note that while 'mouth' in English can be used for many things, 河口 is strictly for rivers. You wouldn't use it for the mouth of a cave (which is 洞穴の入り口) or a person's mouth (which is 口).
- Verb Pairings
- Common verbs include: 流れ込む (flow into), 広がる (spread/widen), 堆積する (accumulate/sediment), and 遡上する (to go upstream from the mouth - often used for salmon).
台風の影響で、河口付近の水位が急激に上昇した。
(Due to the typhoon, the water level near the river mouth rose sharply.)
In more advanced usage, 河口 can be part of compound nouns. 河口堰 (kakou-zeki) refers to a river mouth barrage or weir, a common sight in Japan used to prevent saltwater intrusion into freshwater supplies. If you are describing a landscape, you might say the river mouth is 'magnificent' (壮大な河口) or 'complex' (複雑な河口). When talking about urban development, the word is used to describe the location of industrial zones, which are often situated at the 河口 to facilitate shipping. This word is essential for B1 learners because it bridges the gap between basic nature vocabulary and more specific geographic or environmental descriptions needed for news and academic reading.
You will encounter 河口 (kakou) in several distinct real-world scenarios in Japan. The most common is the Daily News and Weather Reports. Japan is a mountainous archipelago with many rivers; during the rainy season (tsuyu) or typhoon season, the status of major river mouths is critical for flood prevention. News anchors will frequently mention 河口 when discussing tidal surges or the discharge of floodwaters. Another major area is Environmental Education. Japanese students learn about the 'Life of a River' (川の様子) in elementary and junior high school, tracking a river from its source (源流) to its mouth (河口). If you visit a science museum or a nature center near a river, the word will be everywhere on the exhibits describing local flora and fauna.
- Leisure and Tourism
- Fishing enthusiasts are perhaps the most frequent users of the word in a casual context. '河口でシーバスを釣る' (Fishing for sea bass at the river mouth) is a common phrase in hobbyist magazines. Similarly, birdwatchers flock to river mouths to see migratory birds that feed in the nutrient-rich estuaries.
「次の休みは、相模川の河口までサイクリングに行こう。」
("Next holiday, let's go cycling as far as the mouth of the Sagami River.")
Furthermore, 河口 appears in Literature and Song Lyrics. Because it represents a place of transition—where the narrow, defined river meets the vast, infinite ocean—it is often used as a metaphor for leaving home, starting a new journey, or the end of a long struggle. In traditional Enka music or modern J-Pop ballads, the river mouth might be depicted as a lonely, windy place where someone says goodbye. Finally, in Urban Planning, you'll see the word on maps and signs indicating the boundaries of ports and industrial districts. If you take a boat cruise in Tokyo Bay or Osaka Bay, the guide will certainly point out the various 河口 you pass, explaining how they shaped the city's history and economy.
For English speakers learning Japanese, the most frequent mistake with 河口 (kakou) is confusing it with other 'mouth' or 'river' related terms. A common error is using 口 (kuchi) alone. While 'mouth' works for a river in English, in Japanese, saying just 'kawa no kuchi' sounds childish or imprecise. Always use 河口 in writing and formal speech. Another confusion arises with 川岸 (kawagishi), which means 'river bank.' Some learners mistakenly use 河口 to describe the side of the river, but it strictly refers to the end point where it meets the sea. Similarly, don't confuse it with 川下 (kawashimo), which means 'downstream.' While the 河口 is located kawashimo, the words are not interchangeable; one is a specific location, the other is a relative direction.
- Kanji Confusion
- Learners often confuse 河 (ka - large river) with 川 (kawa - general river). While '川口' (Kawaguchi) exists—mostly as a surname or a specific place name—the general geographical term for a river mouth is almost always written as 河口.
❌ 川の口で泳ぐのは危険です。
✅ 河口で泳ぐのは危険です。
(Swimming at the river mouth is dangerous.)
Another subtle mistake is the pronunciation. Ensure you don't confuse kakou (river mouth) with kako (past - 過去) or kakou (processing/manufacturing - 加工). The pitch accent and context usually clarify this, but in writing, the kanji are entirely different. Lastly, be careful with the English word 'estuary.' While 河口 is the best translation, sometimes Japanese uses the more technical 汽水域 (kisuiki) to specifically discuss the biological 'estuary' environment. Using 河口 is generally safe, but in a biology paper, 汽水域 might be more precise. Avoiding these pitfalls will make your Japanese sound much more natural and geographically accurate.
To truly master 河口 (kakou), it is helpful to compare it with related geographical terms. These words often appear in the same context but describe different parts or types of water features. Understanding the nuances between them will allow you to describe landscapes with much greater precision. For example, while 河口 is where a river ends, 源流 (genryū) is where it begins. If you are talking about the shape of the land at the river mouth, you might use 三角州 (sankakusu) for a delta. If the river mouth forms a small, sheltered bay, the word 入江 (irie) (inlet/cove) might be more appropriate. Below is a detailed comparison of these similar terms.
- 河口 vs. 港 (Minato)
- 河口: A natural geographical feature (river mouth).
港: A man-made facility for ships (port/harbor). While a port is often located at a river mouth, the words refer to different things. - 河口 vs. 湾 (Wan)
- 湾: A bay or gulf. A bay is a large body of water partially surrounded by land. A 河口 usually flows into a 湾.
ミシシッピ川の河口には、巨大な三角州が形成されている。
(A huge delta is formed at the mouth of the Mississippi River.)
In technical or scientific contexts, you might encounter 河口域 (kakou-iki), which refers to the 'river mouth area' or 'estuarine zone.' This is slightly more expansive than just the 'mouth' itself. Another related term is 水先 (mizusaki), referring to the area where a pilot guides a ship into the river mouth. For learners at the B1 level, focusing on the pair 源流 (source) and 河口 (mouth) is the most effective way to remember the full lifecycle of a river. By grouping these words together, you create a mental map of Japanese geography that makes the vocabulary much easier to recall during conversations about travel or the environment.
How Formal Is It?
Fun Fact
The kanji '河' is usually reserved for larger, more significant rivers (like the Yellow River), while '川' is for smaller ones. However, '河口' is used for all river mouths regardless of the river's size.
Pronunciation Guide
- Pronouncing it as 'kako' (past), which has a short 'o'.
- Using the English 'mouth' pitch instead of the flat Japanese pitch.
- Confusing it with 'kako' (past) or 'kakou' (processing).
- Over-emphasizing the 'u' at the end.
- Reading '河' as 'kawa' in this compound (it must be 'ka').
Difficulty Rating
Kanji is straightforward but '河' is slightly more advanced than '川'.
Requires remembering the 'Sanzui' radical for '河'.
Pronunciation is easy but must be kept flat.
Can be confused with 'kako' (past) if context is missing.
What to Learn Next
Prerequisites
Learn Next
Advanced
Grammar to Know
Noun + 付近 (fukin)
河口付近で待ち合わせましょう。
Particle まで (made) for limit
河口まで走りました。
Particle にて (nite) - formal locative
河口にて調査を行う。
Compound Nouns (Kanji + Kanji)
河口堰の管理。
Causative Passive (Environment context)
河口の自然が壊されてしまった。
Examples by Level
ここは大きな河口です。
This is a big river mouth.
Simple noun + です structure.
河口に魚がいます。
There are fish at the river mouth.
Locative particle に + います (existence).
河口はあそこです。
The river mouth is over there.
Topic marker は + directional noun.
きれいな河口ですね。
It's a beautiful river mouth, isn't it?
Adjective + noun + sentence ending particle ね.
河口まで歩きます。
I will walk to the river mouth.
Particle まで (until/as far as).
河口はどこですか？
Where is the river mouth?
Question word どこ.
河口の水は冷たいです。
The water at the river mouth is cold.
Possessive particle の.
河口を見ました。
I saw the river mouth.
Object marker を + past tense verb.
週末、河口へ釣りに行きました。
I went fishing at the river mouth this weekend.
Movement particle へ + purpose に + 行きました.
この川の河口はとても広いです。
The mouth of this river is very wide.
Adverb とても + adjective.
河口の近くに公園があります。
There is a park near the river mouth.
近くに (near) used as a location.
船が河口を通っています。
A ship is passing through the river mouth.
Object marker を + verb 通る (to pass).
河口で写真を撮りましょう。
Let's take a photo at the river mouth.
Volitional form ましょう.
河口にはたくさんの鳥がいます。
There are many birds at the river mouth.
Quantity word たくさんの.
自転車で河口まで行けますか？
Can I go to the river mouth by bicycle?
Potential form 行ける.
河口の夕日はとても美しいです。
The sunset at the river mouth is very beautiful.
Compound noun with の.
河口付近では、海水と淡水が混ざり合っています。
Near the river mouth, seawater and freshwater are mixing.
付近 (vicinity) + 混ざり合う (to mix together).
大雨の後は、河口の波が高くなります。
After heavy rain, the waves at the river mouth get high.
Noun + の後 (after) + change of state なる.
この町は、大きな川の河口に位置しています。
This town is located at the mouth of a large river.
位置している (is located).
河口の生態系を守るための活動が行われています。
Activities to protect the ecosystem of the river mouth are being carried out.
〜ための (for the purpose of) + passive 行われている.
台風が近づくと、河口の水位に注意が必要です。
When a typhoon approaches, caution is needed regarding the water level at the river mouth.
Conditional と + noun 注意が必要.
河口から海を眺めるのが好きです。
I like looking at the sea from the river mouth.
Nominalizer の + が好き.
その川は、長い旅を終えて河口にたどり着いた。
The river reached its mouth after a long journey.
たどり着く (to arrive after effort).
河口では、独特の植物が見られます。
Unique plants can be seen at the river mouth.
Potential passive 見られる.
河口堰の建設は、周辺の環境に大きな影響を与えた。
The construction of the river mouth barrage had a major impact on the surrounding environment.
Influence/Impact 影響を与える.
この地域は河口からの堆積物によって形成された三角州です。
This region is a delta formed by sediment from the river mouth.
Passive form 形成された + cause/means によって.
河口域における塩分濃度の変化を調査しています。
We are investigating changes in salinity levels in the river mouth area.
Formal locative における.
鮭は産卵のために、海から河口を通って川を遡上する。
Salmon go upstream from the sea through the river mouth to spawn.
遡上する (to go upstream).
産業廃棄物が河口に流れ込むのを防がなければならない。
We must prevent industrial waste from flowing into the river mouth.
Must-do obligation なければならない.
河口の地形は、潮流や波の影響で常に変化している。
The topography of the river mouth is constantly changing due to the influence of tides and waves.
State of change 変化している.
その港は、河口の入り組んだ地形を利用して作られた。
The port was built by utilizing the intricate topography of the river mouth.
を利用して (using/utilizing).
河口付近の湿地帯は、渡り鳥の重要な休息地となっている。
The wetlands near the river mouth serve as an important resting place for migratory birds.
〜となっている (has become/serves as).
河口における土砂の堆積は、航路の維持に支障をきたすことがある。
The accumulation of sediment at the river mouth can sometimes hinder the maintenance of shipping lanes.
支障をきたす (to cause a hindrance/problem).
都市化に伴い、河口の自然な海岸線が失われてしまった。
With urbanization, the natural coastline of the river mouth has been lost.
に伴い (along with/consequent to).
河口の汽水域は、多様な生物が共生する貴重な空間である。
The brackish water area of the river mouth is a precious space where diverse organisms coexist.
Formal copula である.
地球温暖化による海面上昇は、河口付近の低地に深刻な脅威を与えている。
Sea-level rise due to global warming poses a serious threat to low-lying areas near river mouths.
深刻な脅威を与える (pose a serious threat).
文学において河口は、しばしば生と死の境界として描かれる。
In literature, the river mouth is often depicted as the boundary between life and death.
描かれる (depicted/portrayed).
河口付近の工場地帯からは、かつて大量の汚染物質が排出されていた。
In the past, large amounts of pollutants were discharged from the industrial zones near the river mouth.
Past continuous passive 排出されていた.
この論文は、河口における潮流の力学的特性を分析している。
This paper analyzes the mechanical characteristics of tidal currents at the river mouth.
力学的特性 (mechanical characteristics).
河口の景観を損なわないよう、橋のデザインには細心の注意が払われた。
Meticulous attention was paid to the bridge's design so as not to spoil the landscape of the river mouth.
〜ないよう (so as not to) + 注意が払われる (attention is paid).
河口のデルタ地帯における土地利用の変遷は、その地域の経済史を如実に物語っている。
The transition of land use in the river mouth delta vividly tells the economic history of the region.
如実に物語る (to tell/reveal vividly).
大規模な河口堰の運用にあたっては、生態系への遡及的な影響を慎重に評価すべきである。
When operating large-scale river mouth barrages, the retrospective impact on the ecosystem should be carefully evaluated.
にあたっては (upon/at the time of) + べきである (should).
河口という特異な環境が育んできた文化的なアイデンティティを再考する必要がある。
It is necessary to reconsider the cultural identity nurtured by the unique environment of the river mouth.
育んできた (has nurtured/brought up).
感潮域の最上流部から河口に至るまでの塩分ウェッジの動態をシミュレーションした。
We simulated the dynamics of the salt wedge from the uppermost part of the tidal reach to the river mouth.
に至るまで (reaching up to/as far as).
河口の浚渫作業は、港湾機能の維持と環境保全のジレンマを常に抱えている。
Dredging at the river mouth always carries the dilemma of maintaining port functions versus environmental conservation.
ジレンマを抱えている (to face/hold a dilemma).
万葉集の時代から、河口は歌人たちの想像力を掻き立てる情景として存在し続けてきた。
Since the era of the Man'yoshu, the river mouth has continued to exist as a scene that stirs the imagination of poets.
掻き立てる (to stir up/arouse).
河口における栄養塩の循環は、沿岸域の漁業生産力を支える根幹である。
The circulation of nutrients at the river mouth is the foundation that supports the fishery productivity of coastal areas.
支える根幹である (is the foundation/basis that supports).
河口の地形変動を長期的スパンで捉えるには、衛星データの高度な解析が不可欠だ。
Advanced analysis of satellite data is indispensable for capturing topographical changes in river mouths over a long-term span.
不可欠だ (is indispensable).
Common Collocations
Common Phrases
— To go as far as the river mouth.
散歩で河口まで行きました。
— A wide river mouth.
その川は広い河口を持っている。
— The wind blowing at the river mouth.
河口の風は冷たい。
— A bridge located at the river mouth.
河口の橋を渡る。
— Waves at the river mouth.
河口の波は穏やかだ。
— Sand at the river mouth.
河口の砂は細かい。
— A town located at a river mouth.
彼は河口の町で育った。
— To look out over the river mouth.
展望台から河口を眺める。
— Near the river mouth.
河口の近くに住んでいる。
— The exit of the river mouth (redundant but used).
河口の出口が見える。
Often Confused With
Pronounced the same but means 'crater' of a volcano. Context usually makes it clear.
Pronounced the same but means 'processing' or 'manufacturing'.
Pronounced the same but means 'descent' or 'going down'.
Idioms & Expressions
— To start a journey or venture into the unknown.
新しい事業のために河口に舟を出す。
Metaphorical— To reach the very end of a matter.
学問の河口を極める。
Rare/Literary— Vast and wide like a river mouth.
彼の度量は河口の如し。
Archaic— To wait at a strategic point to catch something.
河口で網を張ってチャンスを待つ。
Idiomatic— The changing tides of fortune.
河口の潮が変わる。
Poetic— Something that has lost its purpose or end goal.
河口を忘れた川のように迷走する。
Metaphorical— To rush toward a conclusion.
物語は河口へ急ぐ。
Literary— An impossible or endless task.
そんなの河口の砂を数えるようなものだ。
Metaphorical— To settle at a transition point.
旅の途中で河口に宿る。
Poetic— The sound of the meeting of river and sea.
静かな夜に河口の声を聞く。
LiteraryEasily Confused
Both relate to river edges.
川岸 is the side (bank) of the river, while 河口 is the end (mouth).
川岸でキャンプをする。
Both refer to the lower part of a river.
川下 is a direction (downstream), while 河口 is a specific spot.
川下には町がある。
Many ports are at river mouths.
港 is a man-made ship facility; 河口 is the natural geographical feature.
横浜港は大きい。
River mouths often flow into bays.
湾 is the large body of sea water; 河口 is the river's exit point.
東京湾に流れ込む。
Both are river endpoints.
源流 is the start (source); 河口 is the end (mouth).
川の源流を探検する。
Sentence Patterns
ここは[Place]です。
ここは河口です。
[Place]へ[Verb]に行きます。
河口へ釣りに行きます。
[Place]付近では、〜が見られます。
河口付近では、珍しい鳥が見られます。
[Cause]によって[Result]が形成された。
堆積物によって河口に三角州が形成された。
[Noun]に伴い、〜が変化している。
都市化に伴い、河口の環境が変化している。
[Noun]は〜の根幹をなしている。
河口の生態系は沿岸漁業の根幹をなしている。
[Noun]に注意が必要です。
河口の水位に注意が必要です。
[Noun]の近くにあります。
河口の近くにあります。
Word Family
Nouns
Verbs
Adjectives
Related
How to Use It
Common in geography, news, and hobbies like fishing.
-
Using '口' (kuchi) alone for a river mouth.
→
河口 (kakou)
In Japanese, 'kuchi' refers to body parts or entrances, but 'kakou' is the specific geographic term.
-
Pronouncing it as 'kako'.
→
kakou (long o)
'Kako' means 'past'. You don't want to say 'I went to the past' when you mean 'I went to the river mouth'.
-
Confusing '河口' with '川岸'.
→
河口 (mouth) vs 川岸 (bank)
One is the end of the river; the other is the side of the river.
-
Using '河口' for a cave entrance.
→
入り口 (iriguchi)
'河口' is exclusively for rivers. For caves, use 'douketsu no iriguchi'.
-
Writing '川口' in scientific reports.
→
河口
While '川口' is used in names, '河口' is the standard academic and geographic spelling.
Tips
The Mouth Visual
Look at '口'. It's a square mouth. The river '河' is flowing right into it. Easy!
Geography Focus
Always use this word when talking about maps or nature. It makes you sound educated.
Watch the 'O'
Make sure the 'ou' in 'kakou' is long. If it's short, people think you are talking about the 'past'.
Summer Festivals
Many fireworks displays happen near '河口' because the wide water is safe for big rockets.
Particle Match
Pair it with '付近' (fukin) to say 'around the area'. It's a very common B1 pattern.
Brackish Water
Associate '河口' with '汽水' (kisuite - brackish). They are best friends in textbooks.
Signposts
Look for the kanji 河口 on road signs near the coast; it often leads to scenic viewpoints.
Kanji Radical
The water radical on the left of '河' tells you it's a water-related word instantly.
Stroke Order
Practice the stroke order for '河' to ensure the 'Sanzui' looks natural.
News Reports
Listen for '河口' during typhoon season news; it's a key word for safety information.
Memorize It
Mnemonic
Think of the river (河) opening its mouth (口) to swallow the sea.
Visual Association
Imagine a giant 'V' shape where a blue river spreads out into a massive ocean, looking like a wide-open mouth.
Word Web
Challenge
Try to find the '河口' of the nearest major river to your home on a map and say its name in Japanese.
Word Origin
Derived from Middle Chinese roots. '河' (hé) originally referred to the Yellow River, and '口' (kǒu) meant mouth or opening.
Original meaning: The opening or exit of a large river.
Sino-Japanese (Kango).Cultural Context
Environmental issues regarding '河口堰' (barrages) can be a sensitive political topic in certain regions of Japan.
In English, 'estuary' sounds scientific, while 'river mouth' is common. In Japanese, '河口' covers both easily.
Practice in Real Life
Real-World Contexts
Weather Forecast
- 河口の水位上昇
- 高潮に注意
- 河口付近の強風
- 避難勧告
Fishing Trip
- 河口でシーバスを狙う
- 潮が動く時間
- 汽水域の魚
- 河口のポイント
Geography Class
- 河口の地形
- 三角州の形成
- 川の終点
- 堆積物の役割
Tourism
- 河口からの景色
- 遊覧船の乗り場
- 河口近くのホテル
- 夕日の名所
Environmental Protection
- 河口の清掃活動
- 生態系の保全
- 水質汚染の調査
- 渡り鳥の保護
Conversation Starters
"この川の河口はどこにあるか知っていますか？"
"河口付近で釣りをそたことがありますか？"
"河口の夕日は本当にきれいだと思いませんか？"
"河口堰についてどう思いますか？"
"日本の有名な河口といえば、どこを思い出しますか？"
Journal Prompts
今日、河口まで散歩に行きました。そこから見えた景色について書いてください。
もしあなたが魚だったら、河口から海に出る時、どんな気持ちになりますか？
あなたの国の有名な河口について、日本語で説明してください。
河口の環境を守るために、私たちができることは何でしょうか？
川の始まり（源流）と終わり（河口）、どちらが好きですか？その理由も書いてください。
Frequently Asked Questions
10 questionsYes, if a river flows into a lake, that point is still called a '河口'. For example, the mouth of a river entering Lake Biwa.
'河口' is the general geographical term. '川口' is often used as a proper noun (place name or surname), though they mean the same thing fundamentally.
It is a standard, neutral-to-formal word. It is the correct term to use in almost all adult contexts.
You use the word '遡上' (sojou) for the act of going up, or '上流' (jouryuu) for the upstream area.
Typically sea bass (suzuki), mullet (bora), and various types of bream (tai) that enjoy brackish water.
In standard Tokyo Japanese, it is 'Heiban' (flat), meaning the pitch stays level after the first syllable.
While '河口' is used, '汽水域' (kisuiki) specifically refers to the brackish water environment of an estuary.
Yes, it can represent the end of a long journey or the point where something small joins something vast.
Very common! Many towns and cities in Japan are named 'Kawaguchi' or 'Kawaguchiko'.
It is a 'river mouth barrage' used to control water flow and prevent salt water from moving too far upstream.
Test Yourself 180 questions
Write a sentence using '河口' and '広い'.
Well written! Good try! Check the sample answer below.
Pronounce 'kakou' correctly emphasizing the long 'o'.
Read this aloud:
You said:
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Listening script: '次のニュースです。利根川の河口で水位が上昇しています。' Where is the water rising?
Describe what you can see at a river mouth in Japanese.
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Translate: 'The ship is entering the river mouth.'
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Write a question asking for the location of the river mouth.
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Translate: 'I like the view of the river mouth.'
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Write a sentence about a typhoon and a river mouth.
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Translate: 'Many people gather at the river mouth.'
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Write a sentence about a boat leaving the river mouth.
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Translate: 'The river mouth was blocked by sand.'
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Translate: 'Let's go to the river mouth tomorrow.'
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Write: 'The river mouth is beautiful.'
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Say: 'Kono kawa no kakou wa hiroi desu.'
Read this aloud:
You said:
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Listening script: '河口から3キロ上流に橋があります。' Where is the bridge?
Write: 'I saw a big ship at the river mouth.'
Well written! Good try! Check the sample answer below.
Write: 'The sunset at the river mouth was orange.'
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Explain 'kakou' in simple Japanese.
Read this aloud:
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Listening: '河口付近の波浪注意報。' What kind of warning is it?
Write: 'Please don't swim at the river mouth.'
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Translate: 'The river mouth is a very dangerous place.'
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Say: 'I want to go to the river mouth.'
Read this aloud:
You said:
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Listening: '河口にゴミを捨てないでください。' What should you not do?
Write: 'I am taking a photo of the river mouth.'
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Write: 'The river flows from the source to the mouth.'
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Say: 'Kono kawa no kakou ni wa sankakusu ga arimasu.'
Read this aloud:
You said:
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Listening: '河口まであと5分です。' How much longer to the mouth?
Write: 'I like fishing at the river mouth.'
Well written! Good try! Check the sample answer below.
/ 180 correct
Perfect score!
Summary
河口 (kakou) is the standard Japanese term for a river mouth. Unlike the English 'mouth,' it is never used for people or caves. Example: 「河口で釣りをします」(I will fish at the river mouth).
- 河口 (kakou) means 'river mouth' or 'estuary,' the point where a river meets a larger body of water like the sea.
- It is composed of the kanji for 'river' (河) and 'mouth' (口), making it easy to remember visually.
- The word is commonly used in geography, weather reports, fishing, and environmental science contexts across Japan.
- Key associations include brackish water (汽水域), deltas (三角州), and tidal influences, making it a B1-level essential word.
The Mouth Visual
Look at '口'. It's a square mouth. The river '河' is flowing right into it. Easy!
Geography Focus
Always use this word when talking about maps or nature. It makes you sound educated.
Watch the 'O'
Make sure the 'ou' in 'kakou' is long. If it's short, people think you are talking about the 'past'.
Summer Festivals
Many fireworks displays happen near '河口' because the wide water is safe for big rockets.
Related Content
More nature words
～上
B1Above; on top of; up.
〜の上
A2On top of, above, upon.
豊か
B1Abundant; rich; plentiful (na-adjective).
〜に従って
B1According to, in conformity with, as (something happens).
酸性雨
B1Acid rain.
営み
B1Activity; daily life; undertaking (e.g., life's activities).
順応する
B1To adapt; to adjust; to conform.
~を背景に
B1Against the backdrop of; with...as background.
空気
A2air
大気汚染
B1Air pollution; the presence of harmful substances in the air.
