Conditionals: と, ば, たら, なら

Japanese has four conditional forms where English has one word. They are not interchangeable, but the distinctions are learnable, and one of them covers most situations you will meet.

〜と: automatic, inevitable results

Used when A always causes B: natural laws, machines, directions. Never for requests, invitations or anything the speaker controls.

• 春になると、桜が咲きます はるになると、さくらがさきますहारु नि नारु तो, साकुरा गा साकिमासुWhen spring comes, the cherry blossoms bloom
• このボタンを押すと、ドアが開きます このボタンをおすと、ドアがあきますकोनो बोतान ओ ओसु तो, दोआ गा अकिमासुIf you press this button, the door opens

〜たら: the general-purpose conditional

Built from the た form: just add ら. It handles hypotheticals, sequences, and "when/once", and it accepts requests and suggestions freely.

• 雨が降ったら、行きません あめがふったら、いきませんअमे गा फुत्तारा, इकिमासेनIf it rains, I won’t go
• 日本に行ったら、京都に行きたいです にほんにいったら、きょうとにいきたいですनिहोन नि इत्तारा, क्योउतो नि इकिताइ देसWhen I go to Japan, I want to visit Kyoto
• 終わったら、教えてください おわったら、おしえてくださいओवात्तारा, ओशिएते कुदासाइWhen you finish, please let me know

〜ば: hypothetical, often written

Formed by changing the final u-sound to an e-sound plus ば. Leans formal and appears often in set phrases and written Japanese.

• 安ければ買います やすければかいますयासुकेरेबा काइमासुIf it’s cheap, I’ll buy it
• どうすればいいですか दोउ सुरेबा ईː देस काWhat should I do? (a very common set phrase)

〜なら: given that, as for

Responds to something just said or established. It attaches straight to nouns, which the others cannot do.

• 京都なら、清水寺がいいですよ きょうとなら、きよみずでらがいいですよक्योउतो नारा, कियोमिज़ुदेरा गा ईː देस योIf it’s Kyoto (you’re asking about), Kiyomizu-dera is good
• 行くなら、傘を持って行って いくなら、かさをもっていってइकु नारा, कासा ओ मोत्ते इत्तेIf you’re going, take an umbrella