The conditional particle と in Japanese is used to indicate a condition that, when met, leads to a specific result. It often translates to if or when in English.
The structure for using と is straightforward. It is attached to the plain form of verbs and sentence-ending adjectives. It is not used directly after formal or polite forms. For example, the part before と won't not end in ます or です.
The condition particle と is used to indicate a natural outcome or consequence that it not controllable.
| If you press this button, the elevator will move. | この ボタン を 押す と、 エレベーター が 動きます。kono botan o osu to, erebeetaa ga ugokimasu. |
| It is scary if the room is dark. | 部屋 が 暗い と 怖い です。heya ga kurai to kowai desu. |
| If you don't get up quickly, you'll be late. | 早く 起きない と、 遅れます よ。hayaku okinai to, okuremasu yo. |
| When it becomes spring, flowers bloom. | 春 に なる と、 花 が 咲きます。haru ni naru to, hana ga sakimasu. |
| When the sun sets, it gets dark. | 日 が 暮れる と、 暗く なります。hi ga kureru to, kuraku narimasu. |
The conditional particle と can also be used in the past tense to mean when A happened, B happened/was the case.
| When I pressed the button, the door opened. | ボタン を 押す と、 ドア が 開きました。botan o osu to, doa ga akimashita. |
| When I returned home, my father was there. | 家 に 帰る と、 父 が いました。ie ni kaeru to, chichi ga imashita. |
Note that the subordinate clause (the condition), is always in the non-past tense, even if the main clause is in the past tense.
The particle と can also be used to describe habits that contain a condition. In this case, you can use と even though you're in control of the outcome.
| When the weather is good, I usually go for a walk. | 天気 が いい と、 散歩 に 行きます。tenki ga ii to, sanpo ni ikimasu. |
| When it rains, I watch movies at home. | 雨 が 降る と、 家 で 映画 を 見ます。ame ga furu to, ie de eiga o mimasu. |
Finally, the condition particle と can be used when giving instructions or directions, but only if the consequence is beyond your control.
| If you go straight on this road, there is a convenience store. | この 道 を まっすぐ 行く と、 コンビニ が あります。kono michi o massugu iku to, konbini ga arimasu. |
| When you cross the street, there is a park. | 道 を 渡る と、 公園 が あります。michi o wataru to, kouen ga arimasu. |
The conditional particle と cannot be used to form commands, requests, suggestions or invitations, so the following sentence is incorrect.
| When you leave the station, please turn right. | 駅 を 出る と、 右 に 曲がって ください。 |
