Expressing That Outcomes Depend on a Variable

～次第だ is an upper-intermediate grammar pattern used to state that an outcome, decision, or situation depends entirely on a specific variable factor.

The grammar pattern ～次第だ, meaning “shidai da,” is an upper-intermediate structure used to express that an outcome, decision, or situation depends entirely on one specific factor. When you use this pattern, you are stating that the result is completely controlled by that single variable. It is a very natural way to explain dependencies in both everyday speech and formal business contexts, such as saying that success rests entirely upon effort, or that a schedule is determined by the weather.

In terms of formation, 次第 must attach directly to a noun. It cannot be attached directly to verb dictionary forms or adjectives. Furthermore, the noun you choose must represent a variable, a state that can change, or something with a range of possibilities. Common nouns used with this pattern include 努力, meaning “effort,” 天気, meaning “weather,” 成績, meaning “grades,” or action nouns like やり方, meaning “way of doing,” and 考え方, meaning “way of thinking.” You cannot use it with static nouns that have no implied variance unless the context clearly makes them a variable condition.

When using this pattern, you will encounter two main structural forms. The predicate forms 次第だ and the polite 次第です are placed at the end of a sentence to simply state "it depends on (noun)". If you want to connect the condition to the result that follows, you use the adverbial forms 次第で or 次第では. Adding は to make 次第では often highlights a specific, sometimes negative or extreme consequence that may happen under certain conditions, such as an event being canceled depending on the weather.

Learners sometimes confuse 次第だ with the pattern ～によって, which also translates to "depending on". The key difference is their focus. The pattern によって highlights that results differ across multiple cases or individuals, such as saying "tastes vary depending on the person". In contrast, 次第 focuses heavily on the idea that the final outcome rests entirely upon one crucial factor, such as "whether we succeed depends on your effort".

Finally, it is very important to avoid confusing this noun pattern with a visually identical grammar point: the verb-ます form attached to 次第. When 次第 follows the ます form of a verb (such as 終わり次第), it takes on a completely different meaning: "as soon as (the action is completed)". To ensure your meaning is always understood as "depending on", strictly attach 次第 to nouns, or convert your verbs into nouns, such as using やり方 instead of the verb directly.