Random Options

Table of contents
  1. 1P / 2P side options
    1. OFF
    2. MIRROR
    3. R-RANDOM
    4. RANDOM
    5. S-RANDOM
  2. DP only options
    1. FLIP
    2. BATTLE
  3. Extra random options
    1. H-RAN
    2. M-RAN
  4. References

random options

1P / 2P side options


Play the chart as it was originally charted. The chart is identical on 1p and 2p side - they are not mirrored to compensate for the turntable’s position. (S1234567 / 1234567S)

Also known as “non-ran” / 正規 (regular).



The button lanes are mirrored left and right (S1234567 -> S7654321).

Also known as 鏡 (mirror).



The R stands for Rotation. The button lanes are shifted left or right. The whole chart could also be mirrored on top of that with 50% chance. It is not possible to get the normal chart (S1234567), or the mirror chart (S7654321).

There are 12 possibilities (source):

  • S2345671 (left shift +1)
  • S3456712 (+2)
  • S4567123 (+3)
  • S5671234 (+4)
  • S6712345 (+5)
  • S7123456 (+6)
  • S1765432 (left Shift +1 and mirrored)
  • S2176543 (+2 and mirrored)
  • S3217654 (+3 and mirrored)
  • S4321765 (+4 and mirrored)
  • S5432176 (+5 and mirrored)
  • S6543217 (+6 and mirrored)

Also known as R乱.



The button lanes are shuffled in a randomized order. There are 7! = 5040 possible permutations for SP. It is still possible to get the original pattern with a very low probability.

Also known as 乱.



Each individual notes are placed on a random lane.

(It is speculated that the algorithm will try to avoid notes that are impossibly close together in the same lane, since it would not be physically possible to press if they are milliseconds apart.)

DP only options


Swaps 1P side and 2P side, including the scratches – see image above. FLIP option is applied first, and then other options (mirror, random) are applied to each side.

dp random options

If you want to mirror the entire DP chart, you need to enable FLIP and turn on MIRROR for both sides.


Duplicates an SP pattern onto both sides. Scores and lamps will not save with this enabled. Cannot be used in STEP UP.


Turning BATTLE on results in DB (double battle) pattern. This isn’t widely used.

Turning BATTLE with MIRROR on one side is DBM (double battle mirror). See more details about DBM here. Turning BATTLE with RANDOM on both sides is DBR (double battle random). Both DBM and DBR are used as training tools for DP players.

Typically, players will turn on AUTO-SCRATCH when using the BATTLE option, since BATTLE may result in patterns that are physically impossible. In fact, when DP players refer to DBR and DBM, they are implying that AUTO-SCRATCH is enabled, unless noted otherwise.


Only possible when BATTLE is enabled; both sides will receive the same random. The resulting chart will not be symmetric; rather, it would be duplicated on both sides.


Only possible when BATTLE is enabled; both sides will receive the same random, but one side will be mirrored, resulting in a symmetric pattern.

Extra random options


(Removed in IIDX 31 EPOLIS.)

Press keypad 8 to activate; S-RANDOM must be selected for this to work. H-RANDOM is like S-RANDOM, except there are additional rules enforced to ensure that you don’t get too many notes in a row in the same lane, which makes it easier than S-RAN. Since this is an assist option, your lamp and score will not save.


Press keypad 6 to activate. This is only applicable when two people are playing at the same time, with random - they will receive the same random, but mirrored on the 2p side.


Back to top

Copyright © iidx.org