In short

Japanese does not have separate words for something, nothing and anything. It builds all three from the interrogative words you already know, by adding one of three endings: か = some-, も (plus a negative verb) = no-, でも = any-. So 何 nani (what) gives 何か nani ka (something), 何も〜ません nani mo …-masen (nothing) and 何でも nan demo (anything at all).

The rule

The whole system is one interrogative word plus one of three suffixes. Learn the three suffixes and you get roughly fifteen pronouns for free.

Step 1 - 疑問詞 + か = indefinite (“some-”)

Attach か to an interrogative and you get the vague, existential member of the set: 何か nani ka (something), 誰か dare ka (someone), どこか doko ka (somewhere), いつか itsu ka (sometime, one day), どれか dore ka (one of them).

These behave like ordinary noun phrases and the predicate stays affirmative: 何か食べます。 (Nani ka tabemasu., “I’ll eat something.”)

In a question, か-indefinites turn a what-question into a yes/no-question. Compare:

• 何を食べましたか。 (Nani o tabemashita ka.) - “What did you eat?” - expects a dish as the answer.
• 何か食べましたか。 (Nani ka tabemashita ka.) - “Did you eat anything?” - expects はい or いいえ.

This is the single most useful contrast in the lesson. Two different か are in play: the sentence-final question particle from Questions with か and interrogative words, and the indefinite か glued to 何. Note that 何か食べましたか。 carries both at once.

Step 2 - 疑問詞 + も + negative predicate = negative concord (“no-”)

Attach も and the sentence must end in a negative: 誰も来ません (dare mo kimasen, “nobody comes”), 何もありません (nani mo arimasen, “there is nothing”), どこにも行きません (doko ni mo ikimasen, “I don’t go anywhere”).

Note what is happening structurally. 誰も is not a negative word - it means something like “even one person”. The negation lives, as always in Japanese, in the verb ending at the end of the sentence. The two halves work as a frame, exactly like あまり〜ない from Adverbs of frequency and degree: once you say 誰も, you are committed to finishing with ません or ない.

The same frame takes counters and quantities: 一つも hitotsu mo (not a single one), 一度も ichido mo (not even once), 一人も hitori mo (not a single person).

Step 3 - 疑問詞 + でも = free choice (“any-”)

Attach でも and you get the opposite of a restriction: 何でも nan demo (anything you like), 誰でも dare demo (anyone at all), どこでも doko demo (anywhere), いつでも itsu demo (any time), どれでも dore demo (whichever one). The predicate is affirmative and the tone is permissive: 何でもいいです。 (Nan demo ii desu., “Anything is fine.”)

Beware the English word any, which covers both Step 2 and Step 3. “I didn’t go anywhere” is the も pattern (どこにも行きませんでした); “I’ll go anywhere” is the でも pattern (どこでも行きます). English uses one word, Japanese uses two different constructions.

Step 4 - Decide what happens to the case particle

This is where learners lose marks, and the rule splits by suffix:

• With も, が and を genuinely disappear. 何も買いません, 誰も来ません - never ×何もを買いません or ×誰もが来ません. In the “no-” sense the も-forms are set adverbial phrases, not a noun plus a case particle, so there is no slot for が or を. (誰もが does exist, but it is the affirmative “everyone” - 誰もが知っています, “everybody knows” - and never the negative “nobody”.)
• With か, が and を are normally dropped, but they are permitted. 何か食べます and 誰か来ました are the neutral forms; 何かを食べます and 誰かが来ました are also correct Japanese - the particle just adds a little focus.
• に, へ, で, と survive, but they sit in different positions depending on the suffix. With か the particle goes after: どこかに行きます. With も and でも the particle goes before: どこにも行きません, どこにでも行きます.

So the pair to memorise is どこかに doko ka ni versus どこにも doko ni mo. Neither ×どこにか nor ×どこもに is used.

Step 5 - ある and いる still split by animacy

Negation does not merge them. Things use ある: 何もありません (nani mo arimasen, “there’s nothing”). People and animals use いる: 誰もいません (dare mo imasen, “there’s nobody”). See Existence with あります／います and position nouns.

Not this lesson

〜か meaning “whether” inside a reported clause - 何を食べるか分かりません (nani o taberu ka wakarimasen, “I don’t know what I’ll eat”) - looks similar but is a different construction: there か closes an embedded question rather than forming a pronoun. It is taught in Quotation と／という／って and embedded questions.

Forms & patterns

The three-way system. Read each row across: same interrogative, three meanings.

Careful with いつも: it is the everyday adverb “always” (いつも七時に起きます), and a negative verb does not turn it into a “no-” word - it only makes it “always … not”, a habit of not doing something. For a real “never” (not even once) reach for 一度も〜ません instead.

Particle placement - the position flips.

Negative-polarity adverbs in the same frame. These are adverbs, not pronouns, but they obey the identical “front half demands a negative back half” logic.

Examples

Common mistakes

• 誰も来ました。 (Dare mo kimashita.) -> 誰か来ました。 (Dare ka kimashita.) - 誰も cannot stand with an affirmative verb. If you mean “someone came”, the indefinite is 誰か; if you mean “nobody came”, the verb must go negative: 誰も来ませんでした。
• どこも行きませんでした。 (Doko mo ikimasen deshita.) -> どこにも行きませんでした。 (Doko ni mo ikimasen deshita.) - the destination particle に does not vanish; it slots in front of も. Only が and を are dropped.
• 何もを買いませんでした。 (Nani mo o kaimasen deshita.) -> 何も買いませんでした。 (Nani mo kaimasen deshita.) - the も-forms take no case particle at all: ×何もを and ×誰もが (in the “nobody” sense) do not exist. With か the particle is merely optional, not forbidden - 何か買いました and 何かを買いました are both correct.
• 部屋に誰もありません。 (Heya ni dare mo arimasen.) -> 部屋に誰もいません。 (Heya ni dare mo imasen.) - negation does not erase the animacy split: people take いる／います, objects take ある／あります.
• 誰でも来ませんでした。 (Dare demo kimasen deshita.) -> 誰も来ませんでした。 (Dare mo kimasen deshita.) - でも is free choice and belongs with an affirmative. English “anyone” maps to も under negation and to でも otherwise.

Tips

• か = some, も = zero, でも = any. Three syllables, three meanings, and they apply to every interrogative word you have learned. Drilling 何か／何も／何でも and 誰か／誰も／誰でも as vertical trios is far more efficient than memorising fifteen separate pronouns.
• Japanese negative concord is not a double negative. 誰も何も言いませんでした (Dare mo nani mo iimasen deshita.) has two “negative” pronouns and one negative verb, and means “nobody said anything” - not “everybody said something”. The negation is counted once, at the verb, no matter how many も-words precede it.
• Particle side: か right, も／でも left. どこかに行く but どこにも行かない. If you can produce that one minimal pair on demand, you have the hardest part of the lesson.
• いつも is the false friend. It is the odd one out of the も-series: it is a perfectly ordinary affirmative adverb meaning “always”, and a negative predicate only makes it “always … not”. For “never”, prefer 一度も〜ません.