次第 details
write + as soon as
kaki shidai
as soon as; the moment X is done
詳しいことが分かり次第、ご連絡いたします。
kuwashii koto ga wakari shidai, go renraku itashimasu.
As soon as we learn more details, we will get in touch. formal
荷物が届き次第、連絡します。
nimotsu ga todoki shidai, renraku shimasu.
As soon as the package arrives, I'll get in touch. neutral
Examples
as soon as; the moment X is done — the second clause must be a volitional, non-past act (a plan, promise, or request), usually by the speaker, even though the first event can happen to anyone or anything
詳しいことが分かり次第、ご連絡いたします。
kuwashii koto ga wakari shidai, go renraku itashimasu.
As soon as we learn more details, we will get in touch. formal
荷物が届き次第、連絡します。
nimotsu ga todoki shidai, renraku shimasu.
As soon as the package arrives, I'll get in touch. neutral
「準備でき次第呼んで！」
junbi dekishidai yonde!
Call me the moment you're ready! casual
Formation
{V-masu-stem}しだいattaches to ます-stem
Notes
Related patterns
Similar
たとたんに reports what happened right after, often as an unplanned jolt (ドアが開いたとたん、猫が逃げた); 次第's SECOND clause must be a volitional, non-past act — a plan, promise or request by the speaker (分かり次第ご連絡します) — never a surprise, even though the first event (分かる) can happen to anyone.
Lookalikes
Same root word, two different attach points and meanings — 見つけ次第 (masu-stem) means "the moment it's found," while N次第で means "depending on N"; skimming past 次第 and missing で flips "as soon as" into "depending on."