ILY Sign, ILYサイン (I Love You Hand Gesture)

In American Sign Language (ASL), the "ILY sign," in Japanese: ai-eru-wai sain ＩＬＹ（アイ・エル・ワイ）サイン, is a hand gesture meaning "I Love You." It's done by extending the little finger and index, bending the ring finger and middle finger, and extending the thumb perpendicular to the index. Like this:

Character: Ranka Lee ランカ・リー
Anime: Macross Frontier, マクロスＦ (Episode 12, Cropped)

• Disambiguation
  • Corna
  • Rumic Sign
• Examples

Disambiguation

The ILY sign is sometimes mistaken for similar hand gestures. One way to tell them apart is that the ILY sign always has the thump perpendicular to the index in order to form the L.

Source: Johannes Kalliauer, via Wikimedia Commons (CC BY-SA 3.0)

Corna

The ILY sign is sometimes mistaken for the corna コルナ, which is that sign associated with rock 'n' roll and the devil. This is what the corna typically looks like:

Character: Shinra Kusakabe 森羅日下部
Anime: En'en no Shouboutai 炎炎ノ消防隊 (Episode 18)

• Context: Shinra awakens.
• rokku-n-rooru!!
  ロックンロール！！
  Rock 'n' roll!!

However, sometimes it's done without holding the thumb against the other fingers, so it's hard to tell if it's supposed to be ILY, corna, or just a random meaningless something else.

Character: Noel ノエル
Anime: Sora no Method, 天体のメソッド (Episode 1)

• Context: is this girl lovely or does she worship the devil?

Rumic Sign

The ILY sign is sometimes mistaken for a rumic sign るーみっくサイン, a hand gesture frequently found in series drawn by Takahashi Rumiko 高橋留美子, used when a character is attacked or surprised.

Character: Makoto マコト
Anime: Minami-ke みなみけ (Episode 2)

Examples

Typically, the ILY sign is used in anime by characters who are idols when making a cute pose, like a peace sign, and it's practically never used to actually mean "I love you."

Character: Kikuchi Makoto 菊地真
Anime: The iDOLM@STER, アイドルマスター (Episode 15, Stitch)

• Context: a double ILY sign.
• kawaiku kaizou saretai!
  かわいく改造されたい
  [I] want to be modified cutely. (literally.)
  
  • In the sense of being transformed into a more cuter version of oneself.

Character: Yazawa Niko 矢澤にこ
Anime: Love Live! School Idol Project (Episode 5)

• Context: a character says her catchphrase, sometimes making a gesture similar to the ILY sign, sometimes making a gesture closer to the corna.
• nikko nikko nii
  にっこにっこにー
  "Nico Nico Smile." (common translation.)
  (meaningless.)
  • The nikko either comes from her name, Niko にこ, or from the mimetic word for smile, niko にこ^[example].
  • If this pose is done with peace signs, it's called an usa-piisu うさピース, "bunny peace," because it looks like bunny ears.