秘伝 · Hiden
The Secret Scrolls
Every master keeps a few techniques that turn hard sums into a single quick move. Study the scrolls, then sharpen them in the dojo.
打 · Addition
Scroll of the Strike
Ten Partners · Twin Strike · Left-Hand Flow · Borrowed Hundred
Open the scroll受 · Subtraction
Scroll of the Block
Step Back · Close the Gap · Through the Gate
Open the scroll連 · Multiplication
Scroll of the Combo
Mirror Stance · Split and Conquer · Eleven Palms · Tiger's Five · Double and Halve · Anchor Squares · Ten Trick · Middle Path
Open the scroll投 · Division & percent
Scroll of the Throw
Reverse Combo · Halve and Halve · Split the Load · Balanced Blade · Coin Sense · Shift the Point
Open the scroll衡 · Equations
Scroll of Balance
Mirror Move · Unwind the Form · Gather the Clan
Open the scroll流 · Fractions
Scroll of Flow
Same Size Pieces · Common Ground · Straight Strike
Open the scroll数 · Dice and quick counting
Scroll of the Tally
Instant Sight · Partner Dice
Open the scroll響 · Logarithms
Scroll of the Echo
Count the Steps · Merge the Echoes
Open the scroll円 · Unit circle and trigonometry
Scroll of the Circle
Height and Width · Half-Circle Rule
Open the scroll环 · Modulo
Scroll of the Mantra
Clock Remainder · Last Digit · Gather then Reduce
Open the scroll刃 · Derivatives
Scroll of the Edge
Power Drop · Clear the Path · Know the Pair
Open the scroll器 · Integrals
Scroll of the Vessel
Reverse the Edge · Power Up · Mirror Cancel
Open the scroll型 · Order of operations
Scroll of the Kata
The Form · Substitute and Strike
Open the scrollChoose your move
Which technique, when?
| Operation | Technique | Best when |
|---|---|---|
| Addition | Left-Hand Flow | Almost any multi-digit sum. |
| Addition | Borrowed Hundred | One number is just below a round number (99, 198). |
| Subtraction | Close the Gap | The numbers are close together (100 − 73). |
| Multiplication | Double and Halve | One number is even, the other ends in 5. |
| Multiplication | Middle Path | Two numbers sit evenly around a round number (19 × 21). |
| Division | Balanced Blade | Both numbers are even — halve them first. |
| Percent | Shift the Point | Any 10 %, 5 % or 20 % calculation. |
The golden rule
Short and daily beats long and rare
Train five minutes in the morning and five in the evening rather than an hour once a week. Your brain stores what you practised while you rest. Use maths in everyday life too — add up prices in the shop, or count the minutes until the bus. If you get stuck, sketch a number line.
Train in the dojo