Scales - Counterfeit Coin and Weighing Puzzles for RPG Maker MZ

Weighing puzzles for your RPG, on a brass balance at a money-changer's counter. One coin in the hoard is false. The player loads the pans, releases the beam, reads which side sank, and names the counterfeit within a set number of weighings. When they name it, the coin is cut open with a banker's chisel to show the lead or copper underneath.

Two puzzles in one plugin. The counterfeit (3 to 13 coins, told or not told whether the false one is heavier or lighter) and the measure: weigh out an exact order of saffron, pepper, salt or tea with a box of weights that may go in either pan. Every mint, hoard and order is generated from a seed. Nothing is loaded from an image file. One plugin command on an event opens it; the event waits, and a switch and a variable tell you how it ended.

And it cannot be guessed. The weighings allowed are the fewest that always suffice, found by an exact search of the whole game before the puzzle is shown (12 coins, not told: three weighings, the classic). The false coin is not fixed in advance: after every weighing it is wherever the weighings so far leave it best hidden. A correct method always wins, and a lucky guess never does.

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⚠️ Compatibility — the question you actually have

Tested against RPG Maker MZ with the stock scripts unmodified, verified by running the plugin in the real engine rather than only in tests.

Plugin Manager order:

1. ScalesCore.js — Scales core - generated weighing puzzles (the counterfeit coin and weighing out a measure), proven winnable by a solver.
2. ScalesDraw.js — Scales draw - the brass balance, generated coins, bell weights, the coin tray, the ledger and the counting-house table, all drawn in code.
3. Scales.js — Scales - weighing puzzles on a drawn brass balance: find the counterfeit coin in a set number of weighings, or weigh out an order.

It extends one core method by saved-original prototype extension, not replaced: Game_System.prototype.initialize.

Because nothing is clobbered, Scales co-exists with other plugins that patch the same seams, including large suites.

What the player sees

• An equal-arm brass balance: a tapered, engraved beam with scrolled ends and a pointer that swings across a graduated arc, pans on chains that hang true as the beam tips, a fluted column on a walnut plinth, all on green baize in candlelight.
• The beam is held level while the pans are loaded. Weigh, and it is released: it swings, overshoots and comes to rest on the heavy side, or rocks and settles level.
• Coins struck in five metals (gold crowns, silver marks, copper pence, electrum staters, bronze obols) with six devices (star, rosette, cross, sun, crescent, tower), three rims and a legend round the edge, laid in a wooden counting tray with a burned number under each.
• A ledger that records every weighing in ink with a small drawn balance showing how it fell, and brass tokens for the weighings left.
• The verdict: the false coin enlarged with a chisel cut through its skin (lead in a heavy one, copper or tin in a light one), the true coins of the hoard beside it, and a brass plaque. For the measure, the goods packed in a folded paper packet sealed with red wax, the weights that did it standing beneath.

Measured, not promised

• The solver's own method, played against the counterfeiter on 360 generated puzzles (120 per difficulty), found the coin within the weighings allowed on every one. A guess before any weighing won 0 of 200 times.
• The weighings allowed match the textbook bounds for every hoard from 3 to 13 coins, and each is the minimum: the same hoard is proven unwinnable in one fewer.
• Whatever coin the verdict shows, won or lost, agrees with every weighing the player made (checked on 200 randomly played games).
• Every measure order balances with its own box; normal and hard orders cannot be made on one pan, and hard ones need at least three weights.
• Over 3,000 seeds the mint generator struck 2,913 distinct coins, covering all 90 metal, device and rim combinations.

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What is in the box

• Three plain, readable JavaScript files: ScalesCore.js (the generator, the solver and the counterfeiter), ScalesDraw.js (the drawing) and Scales.js (the scene and the command).
• The Open Scales command: puzzle, difficulty, number of coins, metal, device, a switch and a variable for the result (1 solved, 2 wrong coin, 0 left), a title and an optional seed.
• Keyboard, mouse and touch. Script calls: Scales.record(key) and Scales.solvedCount().
• Sounds are your project's own sound effects, chosen by name. The plugin ships no audio.

How it was tested

Run in the real RPG Maker MZ runtime from the exact zip you download, installed into a blank project: 57 in-engine checks, including puzzles of every difficulty, metal and device solved through the scene's own paths, a guess that loses, measure orders of every difficulty, the beam's swing and the pans hanging from its ends, a real keyboard (arrows, OK, Shift, Escape) and a real mouse, the command waiting and setting its switch and variable, a solved puzzle reopening at its verdict, and a save and reload. While the player works, a frame costs 2 draw calls.

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From the same studio

• Anvil: a hot-metal forging minigame that forges a pattern from your own weapons and hands back a quality ($12.99).
• Sampler: generated picross charts, finished as a cross-stitch sampler in an embroidery hoop ($11.99).
• Escapement: generated clockwork gear puzzles for every lock in your game ($11.99).
• Derby: a snail race meeting to bet on, with odds measured from the race model ($12.99).
• Tray: generated packing puzzles in inlaid wood, every one solvable and graded by a solver ($9.99).

AI disclosure: the code and the graphics of this product were made with AI assistance. It contains no audio and no narrative text.