Who made it

ScrollChess is written by one person, Andrii Bondar. The same person answers hey@scrollchess.com, which is the whole support department.

What "written by one person" covers

The move rules, the search, the 4 difficulty levels and the piece artwork are this app's own rather than a wrapper around an existing open-source engine. The one thing that came from outside is the puzzle set: 1048 positions from a public-domain (CC0) database, filtered to lines short enough for a wrist and each replayed through the app's own rules before shipping.

Why the numbers on this site are specific

Every figure here was measured on hardware, not estimated. The 4.9 seconds per move comes from a lab build that set positions and timed moves on an Apple Watch Ultra, across 60 moves. The 52,000 positions per second is a rules benchmark run on the watch itself rather than on a Mac, which is the only version of that number worth quoting. A Mac would flatter it by an order of magnitude.

Where a measurement has a limit, the limit is stated with it. The timings are a best case: the largest watch, and the person who designed the input model. That is written down in the post about it rather than left for someone to discover.

Elsewhere

GitHub. One link rather than a row of them: a profile that is not kept up is worse than a profile that was never claimed.

What the app is · Notes · Support