Shikirei: Math Formula Puzzle

A formula is not a question to answer but a device to operate. Place gates at a parabola's zeros, make three lines meet, stack two waves. Predict, observe, adjust.

MOVE THE WORLD WITH EQUATIONS

In this book, an equation is not a question to fill in. It is a mechanism to operate.

Place gates where a parabola meets the ground and send a beam of light to the lighthouse. Choose how the sides of a triangle are divided and see whether three lines meet at one point. Add two waves and match their amplitude and phase.

You never pick an answer from choices. Drag the controls, enter values, and press Observe to see where the light actually lands and which condition was broken. Predict, observe, adjust. There is no attempt limit.

51 UNITS, 153 STAGES

Math I, A, II, B, C and III, with an introductory, an applied and a challenge stage in every unit. Twenty kinds of devices: gates at the zeros of a curve, rods with square-root lengths, probability branches you open and count, gears, waves, tangent lines, integral channels and more. Challenge stages add a resource budget, and some add obstacles and a required order.

• Math I: quadratic functions, radicals, sets, trigonometric ratios, data analysis
• Math A: counting and probability, conditional probability, geometry, integers
• Math II: expressions and proofs, figures and equations, trigonometric functions, exponents and logarithms, differentiation and integration
• Math B: sequences, recurrence relations, statistical inference
• Math C: vectors, the complex plane, conic sections
• Math III: limits, differential calculus, integral calculus

Each unit covers representative topics. This is not a complete collection of every exam question type. The content follows the Japanese high school mathematics curriculum, so some topics and terms may differ from your course.

WORKED EXAMPLES AND ADVICE

• Open the reasoning on the board
• Step through a worked example that shows each action and value (it grants no reward while you watch)
• Ask the stage's spirit for a way of looking at the problem rather than the answer
• Undo and reset are always available

A SECOND MODE: THE UNIVERSE BOOK

60 algebra problems across 11 layers. Each card shows only the name of a technique, such as completing the square, and you compute the numbers in (x + ?)(x + ?) yourself. Answers are checked by expanding back to the original expression, so any valid order of steps is accepted.

TECHNIQUES BECOME CHARACTERS

Sixteen spirits, plus your guide Shiori, each with full-body art and three expressions. Their personalities come from real mathematics: Differentiation and Integration are siblings because of the fundamental theorem of calculus. In this world, fog is what has not yet been proven, and every restored equation clears a little of it.

• Meet a spirit the first time you clear its stage
• The compendium opens each spirit's own explanation of the technique and a bond episode

PRICING

The first 4 units of the Observation Journey (12 stages) and the first three layers of the Universe Book (12 problems) are free, with every feature enabled. A single one-time purchase unlocks the remaining 141 stages and 48 problems. If you purchased before, all 153 stages stay open.

• No additional charges
• No subscriptions
• No ads
• No gacha
• No stamina

WHO IT IS FOR

• You want to feel what a formula actually represents
• You memorized the formulas but do not know when to use them
• You want to start math in the spare minutes before sitting down at a desk
• You keep going when there are characters