Anzan and flash anzan
Anzan (暗算) is mental calculation. Soroban-trained anzan is a particular kind: you picture a soroban and move its beads in your mind with the same moves your fingers make. Expert users hold the numbers as a visual image, rod by rod, rather than as words.
Schools build the image in stages: the real soroban, then covered, then finger movements in the air, then no movement. Abax does this in two skills, after the bead skills.
A1: fading beads
An anzan item is a chain, like a bead drill. The first number is set on the soroban and you see it for a moment (0.8 s). Then the beads fade over 2.5 s: the body of each bead turns to translucent glass first, the highlights stay until late, and in the last quarter everything vanishes. The frame stays. You finish the chain on the soroban you now only imagine, and type the total.
Kojima recommends moving the index finger and thumb in the air as if working real beads.
The A1 ladder: one-digit chains of 2, 3 and 5 numbers untimed, then 5 with gentle timing, then 2-digit chains of 3 (gentle) and 5 (tight). The chains mix addition and subtraction and may use every complement. The Anzan button on the home screen starts an 8-item anzan drill at your current step.
A2 and A3: flash anzan
Flash anzan (フラッシュ暗算) shows numbers one at a time in the same place; you add them as they appear and type the total after the last one. There are no beads on screen at all. The form was developed in Japan by Yūji Miyamoto and is now examined and competed in by the Japanese soroban federations; at the top level, fifteen 3-digit numbers flash in under two seconds.
Each number in Abax is shown for the display time, with a short blank between numbers (12 % of the display time, between 0.04 and 0.2 s) so that two equal numbers in a row still read as two. A run is five rounds; after each answer you see “Correct” or the true total.
The ladders
The display time is per number.
A2, one digit:
| Step | Numbers | Display time | Whole sequence |
|---|---|---|---|
| 1 | 3 | 1.5 s | 4.5 s |
| 2 | 5 | 1.5 s | 7.5 s |
| 3 | 5 | 1.2 s | 6.0 s |
| 4 | 5 | 1.0 s | 5.0 s |
| 5 | 8 | 0.8 s | 6.4 s |
| 6 | 10 | 0.6 s | 6.0 s |
| 7 | 10 | 0.5 s | 5.0 s |
| 8 | 15 | 0.4 s | 6.0 s |
A3, more digits:
| Step | Digits | Numbers | Display time | Whole sequence |
|---|---|---|---|---|
| 1 | 2 | 3 | 1.5 s | 4.5 s |
| 2 | 2 | 5 | 1.2 s | 6.0 s |
| 3 | 2 | 5 | 1.0 s | 5.0 s |
| 4 | 2 | 8 | 0.8 s | 6.4 s |
| 5 | 2 | 10 | 0.6 s | 6.0 s |
| 6 | 3 | 5 | 1.0 s | 5.0 s |
| 7 | 3 | 10 | 0.8 s | 8.0 s |
| 8 | 3 | 15 | 0.5 s | 7.5 s |
Every step is faster, longer or wider than the one before it. The Japan Flash Anzan Association’s exam ladder starts at three one-digit numbers in 5 s (1.67 s each); its tenth dan is fifteen 3-digit numbers in 3 s (0.2 s each). Free flash goes down to 0.2 s.
The usual step-up and step-down rules move you along the ladder; a message says when you moved up or eased back a step.
Free flash
The Flash button on the home screen opens flash anzan with your own
settings: 1 to 4 digits, 2 to 20 numbers, 0.2 to 3.0 s per number. Abax
remembers them (flash_digits, flash_count, flash_ms in the
save file). Answers in free flash are recorded under A2 when
the numbers have one digit and under A3 otherwise.