Conjunctive Particle ので

    • Particle
    Just like the English conjunction "so," ので is a conjunctive particle that explains a reason or cause. It also contains a polite feel, and gets used in formal situations or with people who are not close.

    Table of Contents

    The Basics

    ので is similar to the English conjunction "so." It's a conjunctive particle, meaning it's used to connect two sentences (or you can say, two clauses). And, just like "so," it's used with a reason or cause. In fact, ので is the て-Form of のだ, which is often used to explain reasoning and such.

    An example should give you a better picture — let's see how it works in action. Let's say you are hungry, so you go to a restaurant. Getting hungry is the reason, and going to a restaurant is the result of it. To explain that in Japanese, you can use ので and say:

    • お腹が空いたのでレストランに行きました。
    • I got hungry so I went to a restaurant.

    ので also has a polite feel to it, so this sounds like something you would say to people who you don't know well, or you want to be polite with, such as your teacher or boss.

    Patterns of Use

    The conjunctive particle ので is the て-Form of のだ.

    Connecting Sentences

    The main function of ので as a conjunctive is that it connects sentences together. Let's take a look at the previous example, but this time, with brackets that mark the two sentences inside of the sentence, aka clauses, so that it's extra clear as to what's going on.

    • [お腹が空いた]ので[レストランに行きました]。
    • [I got hungry] so [I went to a restaurant].

    See how ので is connecting the two sentences? This is how a conjunctive particle works. Easy, right? However, just like のだ, you need to be careful when you're using the present form of な-adjectives and nouns with ので — You need to insert な before ので, as in なので. For example, using the noun 二十歳 (twenty years old), you say something like:

    • [二十歳]なので[お酒が飲めます]。
    • [I'm twenty years old] so [I can drink alcohol].

    Without な, as in just 二十歳ので, the sentence is grammatically incorrect. This is the same for all noun-based adjectives, な-adjectives. For example, using the な-adjective, きれい (clean), you can say:

    • [このシャツはきれい]なので[洗濯する必要はありません]。
    • [This shirt is clean] so [there's no need to wash it].

    You may be wondering, "why do we add な?" This is because な historically comes from , which marks nouns and な-adjectives. That said, you could alternatively use です, which also can mark nouns and な-adjectives instead of using な.


    Since です is a politeness marker, 〜ですので sounds extra polite compared to 〜なので.

    の + で Combinations

    There may be times when you spot ので used in a sentence, but it might not be the conjunctive particle ので that we've been discussing on this page. When you see ので, it could just be the combination of the particle の and the particle で. For example, let's say you're buying a new phone, but you can't decide which color you want to get. The sales associate tells you that red is the most popular color right now. You might say:

    • うーん、じゃあ赤いのでお願いします。
    • Um, then the red one, please.

    Although you see ので here, it's actually not the ので we are talking about, the one that's used to explain a reason. This other ので can be broken down into particle の (nominalizer), which turns the い-adjective 赤い (red) into the noun form "the red one." And で is a particle, which can be used for ordering or choosing something at a store or restaurant, often followed by the phrase for a request, お願いします (or not — as it often gets omitted too!).

    Each of the particles の and で have many uses and can mean different things, so keep in mind that ので together might not always be the conjunctive particle used to show a reason. And on top of that, you might stumble upon the combinations of the particles の and で being used for expressing different meanings!

    Beyond The Basics

    ので at the End of a Sentence

    As we mentioned, ので marks a reason, and it's followed by a statement that's based on said reason. It's a conjunctive particle, so it connects two sentences. However, there are times when you don't need the connected statement at the end and you only use the reason marked with ので. For example, your senpai in college is inviting you out for some drinks. You may say something like:

    • 課題があるので・・・。
    • I have some assignments to do, so…

    As you can see, this suggests that you can't join your senpai for drinks. Just like that, by presenting a reason, you can hint what you may be about to say, even though you often end up not saying anything after that. And it's okay, because people usually take the hint and get what you mean through assumption. They will probably actually appreciate your indirect and polite way of rejecting the invitation or offer, or whatever may come off awkward to say explicitly.

    Difference Between ので And から

    Another conjunctive particle for a reason, から, is very similar to ので function-wise. They both indicate a reason and the statement that follows them is based on the reason. What differentiates them is the level and type of politeness each one has. から is often used in casual situations or for people who you are close with. On the other hand, as we mentioned earlier, ので is generally used in formal situations, or with people who you don't know well or who you want to be polite with. For example, if you work at tea shop, and want to warn your customer about a very hot cup of tea, you might say:

    • 熱いので、気をつけてください。
    • It's hot, so please be careful.

    〜ください (please) is a polite way of requesting something, so it suits the polite nuance of ので very well. However, this can come off overly polite or a bit standoffish if you're talking to your friends. For casual situations, から would be a better option. And the tone of the rest of the sentence usually matches the casualness.

    • 熱いから、気をつけてね。
    • It's hot, so be careful.