Does drawing a card during your upkeep trigger Rhystic Study before or after your draw step?

The turn structure is strictly sequential: Untap Step → Upkeep Step → Draw Step (CR 500–504). Any card drawn during the Upkeep Step occurs entirely before the Draw Step starts. Rhystic Study triggers whenever an opponent draws a card, regardless of when in the turn that draw occurs.

Rhystic Study's ability is a triggered ability that watches for any opponent drawing a card (CR 603.1). It does not care whether the draw happens in upkeep, main phase, or combat — if an opponent draws, Study sees it and triggers.

So if an effect during your upkeep (such as another upkeep trigger or an activated ability) causes you to draw a card, Rhystic Study will trigger off that draw. Those triggers go on the stack during the upkeep step, and players get priority to respond before moving to the draw step.

Concrete example: You control Howling Mine and your opponent controls Rhystic Study. Howling Mine's upkeep trigger resolves and causes you to draw a card during your Upkeep Step. Rhystic Study triggers immediately — your opponent may pay {1} or let you draw an additional card. All of this resolves before your Draw Step even begins, at which point you draw your normal card for the turn (which also triggers Study).

Key rule: CR 502.1 defines the upkeep step, and CR 504.1 defines the draw step as a separate, later step. Draws in the upkeep are fully resolved before the draw step, but Rhystic Study (CR 603.1, 603.2) triggers on each draw independently.