First Lesson (Cheot Beonjjae Lesson)

Origin

"First lesson" is an expression that spread after a scene from TVXQ member U-Know Yunho's 2021 solo song "Thank U," in which he calls out "This is the first lesson" and "second lesson," became an internet meme in summer 2025. His solemn, earnest performance ticking off life lessons one by one gets an odd laugh when applied to trivial everyday things.

The comeback was sparked by a streamer. According to a July 2025 News1 report, streamer Looksam spotlighted the "Thank U" music video while making music video reaction content, and when that video took off, clips of U-Know Yunho shouting "first lesson, second lesson" spread across social media as a meme, four years after the song's release.

Spread

The meme's popularity translated into streaming numbers: on Melon, Korea's leading music platform, listeners of "Thank U" rose 56-fold from the previous month. Fans also joined in, including a challenge with the group RIIZE. Around the same time, the press even dubbed it "the second 'Kkang,'" comparing it to Rain's old song that resurfaced amid mocking attention. Gogumafarm put "This is the first lesson~" in the title of its July 2025 meme roundup, noting that the step-by-step, lesson-style structure suits numbered announcements and teaser content.

The man himself also shared his feelings. In a video on the YouTube channel "No Brakes Tak Jae-hoon" released in November 2025, U-Know Yunho said of the comeback, "It felt kind of good... I was grateful and happy, but it was bittersweet. I worried, 'It shouldn't start like this.'" Calling it "a song I poured a lot of effort into" and "a story I'm telling myself," he expressed his hope that the song's sincerity would come through rather than it being consumed only as a joke.

Usage

Solemnly laying out a trivial lesson: "This is the first lesson: ___"
Numbered content in which brands or institutions walk through announcements step by step
Parody videos imitating U-Know Yunho's earnest performance style