If there’s any type of grammar that Japanese is full of, it’s the grammar of probabilities.

Japanese might be hard to learn.

Japanese is probably hard to learn.

Japanese is hard to learn.

Japanese is definitely hard to learn.

There is no doubt that Japanese is hard to learn.

Do they really need grammar functions for all of those sentences, and then some?  Well, unfortunately, language grows in complexity as it grows in beauty.  We can ganbarimasu, though.  一歩勉強すれば。

Begins With One Step Quote

For today, I’ll talk about just one grammar of probability

ni chigainaiにちがいない”there is no doubt that ~; must be ~; no doubt”

With ni chigainai, the speaker is convinced that there is no mistake on his part in guessing something.

Excited Japanese Girl

Here are some examples:

Tomu wa same ga suki ni chigainai.
(Tom must like sharks.)

Ano hito wa nihonjin ni chigainai.
(That person must be Japanese).

“ni chigainai,” when you so desire to use it in a sentence, simply comes after the plain form of whatever comes before it (with one exception).  So:

{ 話す / 話した } に ちがいない
{ hanasu / hanashita } ni chigainai
(someone will no doubt talk / no doubt talked)

{ 食べる / 食べた } に ちがいない
{ taberu / tabeta } ni chigainai
(someone will no doubt eat / no doubt ate)

{ 安い / 安かった } に ちがいない
{ yasui / yasukatta } ni chigainai
(is / was no doubt cheap)

The only exception is for the present/future tense of na-adjectives and nouns, in which case you just put the adjective or noun without ‘da’.  So:

{ 日本人 / 日本人だった } に ちがいない
{ nihonjin/ nihonjin datta } ni chigainai
(someone is / was no doubt Japanese)

Notice, however, that you still include the plain form (datta) for past-tense na-adjectives and nouns.

Are wa Yamaguchi-san ni chigainai.
(That must be Mr. Yamaguchi.)

As compared to…

Are wa Yamaguchi-san datta ni chigainai.
(That must have been Mr. Yamaguchi.)

For more fun with the grammar of probability (because I’m sure it must be a ton of fun), look forward to our lessons on darou, hazu, and kamoshirenai!

Please comment if you find mistakes!  Or for any reason at all :).

Good luck with your studies, everyone.

Keep swimming!


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Yo! I'm Niko, the founder of NihongoShark. I'm also a Japanese translator, writer, and all-around language nerd.

I created this site to help as many people master Japanese (any language, really) as possible.

Uh, what else? Well... I live in Tokyo, Bangkok, Sapporo, Saigon, San Diego, Tokyo, Chiang Mai, Portland, Oregon! So if anyone wants to meet up for a refreshing nama beer, I'm probably down for that. Or a coffee. Learning Japanese is tricky-tikki-tavi. But we're in this together. ファイト!

Good luck with your studies!


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