May one close a box or vessel containing flies on Shabbat?

ShabbatTrapping (Tzad)

Synopsis

The Rema rules one must be careful not to close a small box or vessel with flies inside on Shabbat because it is a pesik reisha (inevitable consequence) that they will be trapped. Some are lenient when the flies would escape upon opening.

Early Acharonim
Late Acharonim
Lenient
Strict
Lesser cited
Major authority

Discussion

Discussion coming soon.

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