dice roll test
dice1d20=

chotto matte kudasai

implemented, it's the same way it works on Futaba Channel
dice1d6=6 is for rolling one traditional dice
!dice1d6= is not a valid dice because it's not the first thing on a new line
dice2d10=6, 5 (11) is rolling two dices from 1 to 10 and showing the total in parenthesis
the upper limit is 20 dices and 9999 faces
attempting more will fail (like below)
dice21d6=
dice1d10000=

ｷﾀ━━━(ﾟ∀ﾟ)━━━!!

dice20d9999=9286, 9090, 2390, 7716, 8240, 6330, 5934, 4502, 7410, 2786, 481, 2081, 2892, 498, 2790, 7430, 5719, 4554, 767, 9241 (100137)

thanks OP
dice1d9999=1146 [b][i][u]

ANUS.PENIS

" rel="nofollow noreferrer" target="_blank">https://ANUS.PENIS this is how many PENISes i hav xD

dice20d9999

>>157656
dice20d9999=761, 4836, 4042, 2700, 1326, 7563, 1261, 1729, 9948, 8428, 2931, 6569, 7570, 1644, 4206, 7280, 387, 992, 185, 745 (75103)

dice1d9001=2364

dice1d6=2
dice2d6=3, 1 (4)
dice1d1=1
dice1d2=2
dice1d2=2
dice1d2=2
testan

dice1d0=

watch this

dice1d1+9000=1 (9001)

but is it smart enough to do more advanced math?
dice2d6+6=5, 4 (15)⁶
dice2d6-6=6, 4 (4)
dice2d6*2=
dice2d6/0=

dice2d6.5=
dice2d6+1.5=
dice20d9999+99999=133, 1779, 3705, 1003, 9018, 3046, 3204, 5125, 8967, 9236, 7924, 3513, 577, 398, 6264, 806, 5189, 5680, 8330, 488 (184384)
dice1.1d6=

it shouldn't be hard to support more complex stuffz, there isn't any use case for them
This one is mostly just a thing because Futaba Channel has them too

inner werkings for the curious
https://github.com/Heyuri/kokonotsuba/blob/main/module/dice/moduleMain.php

Reduced maximum dies from 20 to 10 to be compatible with Futaba Channel

>dice d =とレスするとサイコロを振れる。 はサイコロの数で1～10までの数、 は面の数で1～9999まで設定できるらしい。 振ったあとに出る右側の ()内の数値は左の総和。 東方裏ではお絵描きやカプ、抜くキャラ選びなどによく使われている。

It's also not only 2chan with the same functionality
https://bbs.animanch.com/board/71759/ does the same way
https://wikiwiki.jp/kyoto_doll/%E3%83%80%E3%82%A4%E3%82%B9%E6%A9%9F%E8%83%BD
I'm not very sure if this exact notation is inspired by them like us or it's a known way on Japanese (or globally RPG-related places) internet

>>157744
kaguya (・∀・)

>>157744
translation:
If you reply with dice d =, you can roll dice: the number before the d is how many dice (1–10), and the number after it is how many sides each die has (1–9999). After you roll, the number in parentheses on the right shows the total sum of the dice on the left. On Touhou Ura, people often use it for drawing prompts, pairing characters, or picking which character to fap to.

dice2d10=1, 1 (2)

dice15d6=

dice1d14=12