～次第
as soon as
～次第（しだい）attaches to the masu-stem of a verb (the form left when you remove ます) and means the next action will happen the moment the first one is complete. It corresponds to English “as soon as”.
It belongs to formal, businesslike Japanese: announcements, emails, customer service. The everyday equivalent is ～たらすぐに, choose ～次第 when you want to sound polished. The clause after ～次第 states a plan, promise, or request, it is not used to report something that already happened.
1. Announcing the next step
The speaker commits to acting immediately once a condition is met.
準備ができ次第、出発します。
“We will depart as soon as preparations are complete.”
- 準備（じゅんび）= preparations
- が = subject marker
- でき次第（できしだい）= as soon as (they) are done
- 出発します（しゅっぱつします）= will depart
2. Polite promises in business Japanese
～次第 is extremely common in work emails and phone calls, typically paired with humble or polite verbs.
詳しいことが分かり次第、ご連絡します。
“I will contact you as soon as we know the details.”
- 詳しい（くわしい）= detailed
- こと = thing, matter
- が = subject marker
- 分かり次第（わかりしだい）= as soon as (it) becomes known
- ご連絡します（ごれんらくします）= will contact (you) (polite)
Be careful not to confuse this with noun + 次第で (as in 天気次第で), which is a different pattern meaning “depending on”.
How to form it
Verb masu-stem + 次第
- 終わる（おわる）= to end → 終わり次第（おわりしだい）= as soon as it ends
- 着く（つく）= to arrive → 着き次第（つきしだい）= as soon as (I) arrive
- できる = to be ready → でき次第（できしだい）= as soon as it is ready
Key idea
～次第 is the formal way to say “the instant X is done, Y happens”, a promise of zero delay between one step and the next.
Other N2 grammar
Updated .