Mystique is Minerva's board with one rule changed and two numbers moved. Seven columns are dealt four cards each in rows that alternate face down and face up, so every column hides two cards between the two it shows. Nine more cards form a reserve you may spend one at a time. The last fifteen are the stock, turned once, one card at a time, with no redeal. And where Minerva lets only a king into an empty column, Mystique lets any card in — and keeps the space yours, because the reserve does not refill it.
A space is a tool, so make one. Any card may enter an empty column and nothing fills it for you, so an empty column is worth more here than in almost any Klondike or Canfield relative. Clear a column early — the shallow four-card columns make it possible — and use it to turn over the hidden cards that block the rest of the board.
The reserve is nine chances, in order. You see only the top card and you cannot skip it. Every reserve card played is a new reserve card revealed, so play them whenever the board offers a home; a reserve card sitting unplayable is a locked door in front of eight others.
Fourteen hidden cards, each one move deep. The alternating rows mean no hidden card is under more than one face-up card. A move that reveals is nearly always better than a move that merely tidies, because it tells you what the next move can be.
One pass is the whole clock. Fifteen stock cards, seen once, no way back. Play every tableau and reserve move before each click, and when a stock card cannot be used, remember that it is gone.
The Canfield family is defined by its reserve: a pile of cards you spend one at a time, beside a stock and a small tableau. Minerva is the member that looks least like the family — take the reserve away and it is a Klondike variant with alternating hidden rows. Mystique keeps Minerva's board and shrinks the reserve to nine and the stock to one pass, then lifts the king rule so that a space is an open workspace. That trade — less to play with, more freedom in how you play it — is what makes it a different game rather than Minerva at a different size.
Mystique runs in your browser — free, no download, no sign-up. Install it as an app on your phone or computer and it works offline. You get unlimited undo, a hint button that names a legal move, statistics that track your wins and times, and seeded deals: every game has a seed you can replay, so a board you enjoyed (or lost) can be played again exactly.