ようではないか

The grammar structure ようではないか (also written as ようじゃないか in casual speech) is used to propose or rally others to do something together. It carries a strong sense of encouragement, exhortation, or appeal, making it common in speeches, formal proposals, and situations where the speaker wants to inspire collective action. It is more emphatic and persuasive than the simple volitional form (～よう).

It corresponds to "Let's do it!" or "Why don't we…!" with a rallying, motivational tone.

Formation

Attach ようではないか to the verb stem (the same stem used for the volitional form):

• V1 (る-verbs): Remove る and add ようではないか

  • かんがえる考える → 考えようではないか

• V5 (う-verbs): Change the final う-row kana to the お-row equivalent and add うではないか

  • がんばる頑張る → 頑張ろうではないか
  • はなしあう話し合う → 話し合おうではないか

• Irregular:

  • する → しようではないか
  • くる来る → 来（こ）ようではないか

Usage and nuance

This pattern is used when addressing a group and encouraging everyone to take action together. It has a formal, somewhat rhetorical quality and is frequently heard in speeches, presentations, and written appeals.

Casual variant: ～ようじゃないか

In more casual or spoken contexts, ではないか is often shortened to じゃないか:

Comparison with ～ましょう and ～よう

While 〜～ましょう is a polite invitation and the plain volitional 〜～よう is a casual suggestion, ようではないか adds a layer of persuasion and enthusiasm. It is less about a simple suggestion and more about rallying people toward a shared goal. It would sound unnatural to use this pattern for everyday, mundane proposals like "Let's eat lunch."