In short

Japanese has hundreds of verbs in pairs: an intransitive one for “it happens” (ドアが閉まります doa ga shimarimasu, “the door closes”) and a transitive one for “someone does it” (ドアを閉めます doa o shimemasu, “I close the door”). The intransitive takes が, the transitive takes を - and picking the wrong half of the pair is the single most audible A2 error. Once you have the pairs, 〜てある lets you describe a state and imply that a person put it there on purpose.

The rule

English reuses one verb for both jobs: “the door closes” and “I close the door”. Japanese uses two different verbs, and the ending tells you which is which.

Step 1 - Decide whether you are describing an event or naming a doer.

• No doer in view, the thing just does it -> intransitive (自動詞 jidōshi), particle が.
• Someone acts on the thing -> transitive (他動詞 tadōshi), particle を.

Step 2 - Match particle to verb, not to meaning. The pattern is fixed:

• Noun + が + intransitive verb: 電気がつきました (denki ga tsukimashita) - “the light came on.”
• Noun + を + transitive verb: 電気をつけました (denki o tsukemashita) - “I turned the light on.”

You cannot mix them. ×電気をつきました is ungrammatical, not merely odd.

Step 3 - Learn the endings, not fifteen isolated words. The pairs are built from a small number of recurring shapes. A verb ending in 〜su is almost always the doer-verb (消す, 出す, 落とす, 直す), and one ending in 〜aru is almost always the happens-verb (閉まる, 始まる, 決まる). Do not trust 〜eru the same way: 消える kieru and 割れる wareru end in 〜eru and are intransitive. See the family table below.

Japanese prefers the intransitive. Where English says “they cancelled the meeting” or “I broke a glass”, ordinary Japanese says 会議が中止になりました or コップが割れました (koppu ga waremashita, “the glass broke”). Naming an agent is treated as extra information: if it does not matter, leave it out and let the intransitive carry the sentence. This is why train doors say ドアが閉まります and not “we are closing the doors.”

〜てある: a state that somebody made. Take the transitive verb, put it in the て-form, and attach ある:

Noun + が + V(transitive)-て + あります

窓を開ける -> 窓が開けてあります (mado ga akete arimasu) - “the window is open (someone opened it, on purpose, and left it that way).” The auxiliary is always ある, never いる, whatever the noun is - it is the situation that exists, not the object. It conjugates like ある: あります／ありません／ありました。

The three-way contrast - learn it as one system.

The first two describe the same physical scene; only the implication differs. 〜てある answers “who set this up?” without naming anybody. 〜ておく is the action that produces a 〜てある state - it belongs to the te-form auxiliaries, so treat it here only as the other end of the same story.

The を variant. You will also meet Noun + を + V-てあります: ホテルを予約してあります (hoteru o yoyaku shite arimasu) - “I’ve booked the hotel (it’s taken care of).” With が the focus is on the object and its state; with を the focus is on the task being already done, which is why it feels close to 〜ておく.

One hard limit: 〜てある attaches to transitive verbs only. ×窓が開いてあります is impossible, because 開く is intransitive. If you want the state of an intransitive verb, use 〜ている.

Forms & patterns

The core pairs. Left column takes が, right column takes を.

(I) = Group I 五段, (II) = Group II 一段 - you need this for the て-form.

The recurring shapes. Four families cover almost everything above.

Building 〜てある.

Examples

Common mistakes

• ドアを開きました。 (Doa o akimashita.) -> ドアを開けました。 (Doa o akemashita.) - 開く read aku is the intransitive half and can never take を. To name yourself as the doer you need the transitive 開ける. (The same kanji read hiraku is a different verb that does take を - 本を開く hon o hiraku, “open a book” - but for doors and windows the everyday pair is 開く aku ／ 開ける akeru.)
• 電気が消えてあります。 (Denki ga kiete arimasu.) -> 電気が消してあります。 (Denki ga keshite arimasu.) - 〜てある is built on the transitive verb only. 消える is intransitive; its partner 消す is what you need.
• 窓が開けています。 (Mado ga akete imasu.) -> 窓が開いています。 (Mado ga aite imasu.) - a transitive verb plus ている describes somebody in the act of doing it, so it needs a person and を (先生が窓を開けています). For the plain state of the window, use the intransitive.
• 会議が始めます。 (Kaigi ga hajimemasu.) -> 会議が始まります。 (Kaigi ga hajimarimasu.) - an event that simply starts takes the intransitive. Use 始める only when a person starts something: 会議を始めます。
• 財布が見つけました。 (Saifu ga mitsukemashita.) -> 財布が見つかりました。 (Saifu ga mitsukarimashita.) - “it turned up” is 見つかる with が; “I found it” is 財布を見つけました with を. The particle and the verb must agree.

Tips

• Trace the vowel before る. Across most pairs, the transitive verb has an e in the syllable before the ending (閉めmeる, 始めmeる, 決めmeる, 開けkeる), while the intransitive has a or i (閉まmaる, 始まmaる, 落ちchiる). It is not a law - the 〜eru／〜u family runs the other way, so 割れる wareru is the intransitive and 割る waru the transitive - but everywhere else it is a reliable first guess.
• Learn each pair as one flashcard, with its particle glued on: 「ドアが閉まる／ドアを閉める」. Learning 閉まる and 閉める on separate days is how learners end up guessing for years.
• Signage and notices live on these forms. Public wording is overwhelmingly intransitive or 〜てある: ドアが閉まります (doa ga shimarimasu) on trains, ここに書いてあります (koko ni kaite arimasu, “it’s written here”) when someone points at a notice. If a sign confuses you, ask first which half of the pair it uses.
• Do not hear an English passive. 窓が開けてあります is not “the window was opened by someone” as a passive sentence - Japanese has a real passive for that, and it carries a different flavour, often of nuisance. 〜てある is calm and practical: the thing is ready.