予想する

The Japanese verb 予想する (yosou suru) is a fundamental term for anyone looking to describe the act of looking into the future. At its core, it translates to 'to forecast,' 'to predict,' or 'to anticipate.' However, the nuance is slightly more structured than a mere 'guess.' The word is composed of two kanji: 予 (yo), meaning 'beforehand' or 'previously,' and 想 (sou), meaning 'thought,' 'concept,' or 'imagination.' Together, they describe the mental process of forming a concept of an event before it actually occurs. This isn't just about psychic predictions; it is the logical extension of current information into a future state. In Japanese society, where planning and risk management are highly valued, 予想する plays a critical role in both professional and personal spheres. Whether you are a weather forecaster analyzing satellite data or a student wondering if an exam will be difficult, you are engaging in the act of yosou.

Cognitive Process

The verb implies a level of reasoning. While 'suisoku' (conjecture) might be based on thinner evidence, 'yosou' suggests you have some basis—be it past experience, data, or a logical trend—to support your claim. It is the standard word for sports betting, stock market predictions, and weather forecasting.

When using this word, it is important to understand its social weight. In a business meeting, saying 'I predict sales will increase' using 予想する sounds professional and analytical. It suggests that you have looked at the charts and come to a conclusion. In contrast, using a word like 'omou' (to think) would sound more like a personal opinion rather than a professional forecast. The word is also frequently used in the passive voice or as a noun. For example, 'yosou-gai' (unexpected) is a very common expression used when something happens that was 'outside of the prediction.' This highlights how much Japanese culture relies on these mental models of the future; when something falls outside the yosou, it is noteworthy enough to have its own specific vocabulary.

Daily Life Usage

In daily life, you might use it when talking about the weather, the outcome of a TV show, or even how a friend might react to a gift. It is versatile but maintains a sense of 'calculating' the future.

Furthermore, the word often appears in news headlines. 'Keizai-seichou o yosou suru' (Predicting economic growth) or 'Senkyo-kekka o yosou suru' (Predicting election results) are standard phrases. The breadth of its application—from the triviality of a coin toss to the complexity of global economics—makes it one of the most useful verbs for an intermediate learner to master. It bridges the gap between simple 'thinking' and complex 'analysis.' By using 予想する, you signal to your listener that you are not just guessing randomly, but that you are applying your mind to the possibilities of what is to come.

Using 予想する correctly requires an understanding of Japanese sentence structure, specifically how to link the 'prediction' to the verb. The most common way to express what you are predicting is by using the object marker を (o) or the quotation particle と (to). If you are predicting a specific noun, like 'the weather' or 'the result,' you use [Noun] を予想する. For example, 'Kekka o yosou suru' (Predict the result). However, if you are predicting a full action or state, you use the plain form of the verb followed by だろうと予想する or simply と予想する. This is similar to saying 'I predict that...' in English.

The 'To' Particle Pattern

When you want to describe the specific content of your prediction, use the structure: [Sentence in Plain Form] + と予想する. Example: 'Ashita wa hare da to yosou suru' (I predict that tomorrow will be sunny).

Another important grammatical point is the tense. Because a prediction is about the future, the verb 予想する itself is often in the present tense when stating a current belief about the future. However, if you are talking about a prediction you made in the past that has now been proven right or wrong, you would use the past tense 予想した. For example, 'Watashi wa kou naru to yosou shita' (I predicted it would turn out like this). This is often followed by 'touri' (as expected) or 'hazureta' (missed/wrong). Understanding these collocations is key to sounding natural.

Passive and Potential Forms

In formal reports, you might see 'yosou sareru' (it is predicted that...). This removes the subject and makes the statement sound more objective. 'Yosou dekiru' (can predict) is used when something is foreseeable.

Finally, consider the level of certainty. If you are very sure, you might add adverbs like 'kakujitsu ni' (certainly) or 'osoraku' (probably). 'Osoraku ame ga furu to yosou shimasu' (I predict it will probably rain). The verb 予想する provides the frame, and the surrounding particles and adverbs provide the detail. Mastering the transition from the simple 'Noun o yosou suru' to the more complex 'Clause to yosou suru' marks a significant step in Japanese proficiency, allowing you to discuss logic and probability with ease.

If you turn on a Japanese television, you are almost guaranteed to hear 予想する within the first thirty minutes. One of the most common environments is the weather report. While 'yohou' (forecast) is the official noun for the weather forecast, the meteorologists often describe the process of 予想する when explaining how they reached their conclusions. They might say, 'Kongo no shinro o kou yosou shite imasu' (We are predicting the future path [of the typhoon] like this). This usage emphasizes the ongoing analytical process of the experts.

Sports and Gambling

In the world of 'Keiba' (horse racing) or 'Kyotei' (boat racing), 'yosou' is the king of words. Fans buy 'yosou-shi' (prediction sheets) and spend hours 'yosou suru' the winners. Here, it takes on a slightly more speculative but still 'calculated' tone.

In the business world, 予想する is indispensable. During quarterly reports, CEOs will 'yosou suru' the next year's profits. This is a formal, high-stakes environment where the word implies accountability. If a company's 'yosou' is too far off from the 'jisseki' (actual results), it can lead to a drop in stock prices. Therefore, you will hear it in phrases like 'gyouseki yosou' (earnings forecast). In this context, the word is synonymous with professional foresight and strategic planning.

Academic and Scientific Research

Scientists use 'yosou suru' when discussing hypotheses. 'Kono jikken de wa, tsugi no you na kekka o yosou shite imasu' (In this experiment, we are predicting the following results). It is the standard term for a scientific prediction.

Lastly, you will hear it in casual conversations among friends. When watching a movie, someone might say, 'Hannin wa dare da to yosou suru?' (Who do you predict the killer is?). Or when waiting for a mutual friend who is always late, 'Kare wa nan-ji ni kuru to yosou suru?' (What time do you predict he will arrive?). In these cases, it adds a playful layer of 'making a bet' or 'testing one's intuition' to the conversation. Whether in the boardroom or the living room, 予想する is the go-to verb for engaging with the unknown future.

One of the most frequent mistakes English speakers make with 予想する is confusing it with 予定する (yotei suru). While both involve the future, they are fundamentally different. 予定する means 'to plan' or 'to schedule.' It implies intention and control. If you say 'Ashita ame o yotei suru,' you are saying you have scheduled the rain, which is impossible (unless you are a weather god). Instead, you must use 予想する because the weather is something you observe and forecast, not something you control. Remember: Yotei is for your calendar; Yosou is for your crystal ball (or data charts).

Yosou vs. Yosoku

Another common point of confusion is between 'yosou' and 'yosoku' (予測). While often interchangeable, 'yosoku' is more technical and data-driven. Use 'yosou' for general predictions and 'yosoku' for scientific or statistical ones. Using 'yosoku' for a casual guess about a movie ending might sound overly robotic.

Another mistake involves the particle usage. Some learners try to use に (ni) with 予想する, perhaps thinking of 'predicting *to* someone.' However, 予想する is a transitive verb that takes the object を (o). You predict *something*. If you want to say you told your prediction to someone, you would say 'Yosou o [person] ni tsutaeru.' Also, be careful with the nuance of 'expectation.' While 予想する can mean 'anticipate,' it doesn't carry the emotional weight of 'hoping for' something. For that, you should use 期待する (kitai suru). If you say 'I predict a good gift,' it's a logical guess. If you say 'I expect (hope for) a good gift,' it's kitai.

Transitive Nature

Remember that 'yosou' is something you *do* to an object. You cannot just say 'I predict' (Watashi wa yosou suru) without an object or a 'to' clause in most natural conversations, as it leaves the listener hanging: 'Predict what?'

Finally, watch out for the negative form. 'Yosou shinai' means you don't make a prediction. But if you want to say something was 'unexpected,' the noun form 予想外 (yosou-gai) or the phrase 予想していなかった (yosou shite inakatta) is much more common. Beginners often try to invent words like 'fu-yosou,' which don't exist. Stick to the established patterns to avoid sounding unnatural. By distinguishing between planning, expecting, and predicting, you will use 予想する with the precision of a native speaker.

Japanese has a rich vocabulary for the future, and 予想する is just one piece of the puzzle. To truly master the language, you need to know when to use its cousins. The most direct alternative is 予測する (yosoku suru). While very similar, 予測 (measurement + thought) is used for predictions based on hard data, statistics, or scientific measurements. You 'yosoku' the population in 2050 using a computer model, but you 'yosou' who will win a popularity contest. In many cases they are interchangeable, but yosoku sounds more 'scientific.'

Yosou vs. Suisoku

'Suisoku suru' (推測する) translates to 'conjecture' or 'guess.' This is used when you have very little evidence. If you see a person crying and 'guess' they are sad, that is suisoku. 'Yosou' implies a bit more of a forward-looking, structured thought process.

Another interesting alternative is 予言する (yogen suru). This means 'to prophesy' or 'to predict' in a supernatural or absolute sense. Nostradamus 'yogen' the end of the world. You would never use 予想する for a religious prophecy, nor would you use 予言する for a weather report (unless the weatherman thinks he is a prophet). Then there is 予感する (yokan suru), which means 'to have a premonition' or 'to have a hunch.' This is entirely based on feeling and intuition, not logic. 'I have a bad feeling about this' is 'Iya na yokan ga suru.'

Formal Alternatives

In very formal or literary contexts, you might encounter 'yodan' (予断), which means 'prejudgment.' It is often used in the negative: 'Yodan o yurusanai' (The situation allows for no prejudgment/is unpredictable).

Finally, consider 見込む (mikomu). This verb means 'to expect' or 'to anticipate' in a business sense, often regarding numbers or potential. 'Rainen no uriage o mikomu' (Anticipate next year's sales). It carries a nuance of 'factoring something into your plans.' While 予想する is about the mental act of predicting, 見込む is about the practical act of accounting for that prediction. By choosing the right word from this set, you can express exactly how you are looking at the future—whether with a calculator, a crystal ball, or just a gut feeling.