Based on bridgewebs.com slides and bridgehands.com post

XYZ is in effect whenever our side has made 3 (or more) bids at the one level, and it’s Responder’s turn to bid:
1-1-1, 1-1-1, 1-1-1NT, 1-1-1, 1-1-1NT, 1-1-1NT, 1-1-1, 1-1-1NT, 1-1-1NT, 1-1-1NT, or even 1-1-1-1-1NT.

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