In the intro sequence there's a glimpse of a comely witch clamped to an upright ring-shaped apparatus, but we don't get a better view until episode #8. Later in the same episode a younger girl (though disguised as a boy) is attached to the same apparatus for a longer period.
At the end of episode #9 the same girl has her wrists roped behind her (specifically a quick closeup of the knot being tightened). This is repeated at the beginning of episode #10, and she stays tied up for much of the remainder of the episode.
(Sorry, couldn't catch run times for the above.)
Anime Sightings Old and New - Grimoire of Zero
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