Genre plays an important role in the music select process in SEGA's music games, similar to Taiko no Tatsujin prior to Nijiiro version. Each song can only belong to one genre. The genre structure has changed multiple times in the maimai and CHUNITHM series, and as of 2020, SEGA has mostly unified the genre structure among all three games. This wiki takes advantage of this unification, and put songs into categories based on their genres.

maimai

History of genres in maimai
J-Pop Overseas pop Anime Non-SEGA game SEGA game Crossed over original songs maimai original Joypolis Vocaloid Touhou
1st J-POP OVERSEAS GAME/ANIME ORIGINAL VARIETY
1st+ J-POP OVERSEAS GAME/ANIME ORIGINAL JOYPOLIS VARIETY
GreeN POPS ANIME GAME ORIGINAL JOYPOLIS VARIETY
GreeN+ ~ ORANGE+ POPS ANIME GAME ORIGINAL JOYPOLIS niconico 東方Project
PiNK ~ FiNALE POPS & ANIME GAME & VARIETY SEGA ORIGINAL & JOYPOLIS niconico & VOCALOID 東方Project
DX POPS & ANIME VARIETY ORIGINAL niconico & VOCALOID 東方Project
DX+ ~ POPS & ANIME GAME & VARIETY ONGEKI & CHUNITHM maimai niconico & VOCALOID 東方Project

Songs originally from Crackin' DJ were listed as ORIGINAL pre-GreeN+.
"VARIETY" and "COLLABO" genres existed from GreeN+ to ORANGE+. Songs in these two genres were split into other genres since PiNK.
"VARIETY" in _~GreeN is just Vocaloid + Touhou, and is different from "VARIETY" in GreeN+~ORANGE+. "GAME & VARIETY" in PiNK != "GAME" + "VARIETY" in ORANGE+.
BMS songs, added since GreeN+, are always in the "(GAME &) VARIETY" genre.

VARIETY and COLLABO genres in ORANGE+
GreeN+ ORANGE ORANGE+ PiNK
L9 N/A N/A VARIETY G&V
B.B.K.K.B.K.K. N/A VARIETY VARIETY G&V
DRAGONLADY VARIETY VARIETY VARIETY G&V
Jack-the-Ripper◆ VARIETY VARIETY VARIETY G&V
林檎華憐歌 VARIETY VARIETY VARIETY n&V
バラライカ VARIETY VARIETY VARIETY P&A
おても☆Yan N/A VARIETY VARIETY O&J
ソーラン☆節 VARIETY VARIETY VARIETY O&J
炭★坑★節 VARIETY VARIETY VARIETY O&J
デコボコ体操第二 ORIGINAL VARIETY VARIETY O&J
NIGHT OF FIRE POPS VARIETY VARIETY P&A
ウッーウッーウマウマ(゚∀゚) POPS VARIETY VARIETY P&A
YATTA! POPS VARIETY VARIETY P&A
Tachyon POPS VARIETY VARIETY P&A
galaxias! POPS VARIETY VARIETY n&V
レッツゴー!陰陽師 VARIETY VARIETY VARIETY G&V
GO MY WAY!! COLLABO COLLABO COLLABO G&V
THE IDOLM@STER 2nd-mix COLLABO COLLABO COLLABO G&V
The world is all one !! COLLABO COLLABO COLLABO G&V
タカハせ!名人マン COLLABO COLLABO COLLABO O&J
maiム・maiム feat.週刊少年マガジン ORIGINAL COLLABO COLLABO O&J
DADDY MULK -Groove remix- COLLABO COLLABO COLLABO G&V
電車で電車でGO!GO!GO!GC! -GMT remix- COLLABO COLLABO COLLABO G&V
RIDGE RACER STEPS -GMT remix- COLLABO COLLABO COLLABO G&V
ファンタジーゾーン OPA-OPA! -GMT remix- COLLABO COLLABO COLLABO G&V
オパ! オパ! RACER -GMT mashup- COLLABO COLLABO COLLABO G&V
電車で電車でOPA!OPA!OPA! -GMT mashup- COLLABO COLLABO COLLABO G&V
リッジでリッジでGO!GO!GO! -GMT mashup- COLLABO COLLABO COLLABO G&V
FLOWER N/A COLLABO COLLABO G&V
Scars of FAUNA N/A COLLABO COLLABO G&V
きたさいたま2000 N/A COLLABO COLLABO G&V
Ignis Danse N/A COLLABO COLLABO G&V
Got more raves? N/A COLLABO COLLABO G&V
FUJIN Rumble N/A COLLABO COLLABO G&V
Garakuta Doll Play ORIGINAL COLLABO COLLABO O&J
VERTeX N/A COLLABO COLLABO O&J

CHUNITHM

Pops & Anime niconico Touhou Project Other music game Non-music game Irodorimidori Kotonoha Project Other crossed over original songs CHUNITHM original
1st ~ 1st+ POPS & ANIME niconico 東方Project VARIETY GAME ORIGINAL
AIR POPS & ANIME niconico 東方Project VARIETY GAME イロドリミドリ ORIGINAL
AIR+ POPS & ANIME niconico 東方Project VARIETY GAME イロドリミドリ 言ノ葉Project ORIGINAL
STAR ~ AMAZON+ POPS & ANIME niconico 東方Project VARIETY イロドリミドリ 言ノ葉Project ORIGINAL
CRYSTAL ~ POPS & ANIME niconico 東方Project VARIETY イロドリミドリ ゲキマイ ORIGINAL

Irregular genre

オンゲキ

The genre structure didn't change: オンゲキ, POPS & ANIME, niconico, 東方Project, VARIETY, チュウマイ