On the Japanese side of the internet, November 28th is known as the Good Knee High Socks Day, an unofficial anniversary day for over-knee socks, usually called Knee Highs. Funnily enough, it started as a minor joke in 2010, in 2011 Japanese illustrators pixiv users began posting illustrations under the tag “Good Knee-High Socks Day” but it took off as an actual anniversary in 2013, and since then it has been an annual event among Japanese Twitter users to upload Knee-High photos, illustrations or selfies with hashtag #いいニーハイの日 on Twitter.
In Japan, there are many unofficial but widely-known anniversary days designated by companies, organizations, industrial groups or persons for their promoting/awareness campaigns. Many of them enacted by a simple wordplay of dates numbers, which manner comes from a Japanese language’s characteristic that Kanji characters including numbers usually have multiple pronunciations. Additionally, “wordplay” anniversary days tend to be designated in November because “11” can be read as “I(1)I(1)” which is meaning of “Good”, “Nice” or “Happy”.
3/10: “Suger Day” → 3[Sa] + 10[Tou] = Satou = Suger
3/19: “Music Day” → 3[Myū] + 1[(Z)i] + 9[Ku] = Music
5/30: “No Garbage Day” → 5[Go] + 3[Mi] = Gomi = Garbage & Zero(0)
6/9: “Rock (Music) Day” → 6[Ro] + 9[Ku] = Rock
8/7: “Nose Day” → 8[Ha] + 7[Na] = Hana = Nose
10/2: “Tofu Day” → 10[Tou] + 2[Fu] = Toufu
11/22: “Good Married Couple Day” → 1[I] + 1[I] = Ii = Good & 2[Fū] + 2[Fu] = Fūfu = Married Couple
29th of Every Month: “Meat Day” → 2[Ni] + 9[Ku] = Niku = Meat
In the same manner, Good Knee-High Socks Day is designated on November 28th since the numbers can be read as “1[I] + 1[I] + 2[Nī] + 8[Ha(i)]” which is meaning of “Good Knee-Highs.” Meanwhile, the dawn of this anniversary day hadn’t come till the late 2000s because it inherited a famous moe concept Zettai Ryouiki, or a fetish for the area of bare skin in the gap between over-knee socks and a miniskirt, that was established in the otaku culture in the first half of 2000s.
https://twitter.com/_104channn/status/1067441270744731648
https://twitter.com/BSJ_YUUKI/status/1067439339305496582
ももの付け根がむちむちすぎて
もうけつ始まってんのやけど#いいニーハイの日 pic.twitter.com/5bSNGS0ImG
— 篠原みなみ (@snhr_minami) November 27, 2018
https://twitter.com/X27E57/status/1067535426829737984
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https://twitter.com/Calpas_oishiiii/status/1067467642766688256
#いいニーハイの日 も、名古屋においでよ。 pic.twitter.com/P1Ru5r8ldC
— おいでよ名古屋@おいなご (@oinagoya) November 27, 2018
https://twitter.com/koikecos/status/1067440210101727233
https://twitter.com/banko003/status/1067467116276633600
よくないニーハイしかない
#いいニーハイの日 pic.twitter.com/EwzrQVzwXO— 森近りん (@sneer0344) November 27, 2018
11月28日はいいニーハイの日!精霊使いの剣舞ドラマCDの発売日です!
にーはいふぁいっ!#いいニーハイの日 pic.twitter.com/WXJMnCHtku— 志瑞祐@聖剣学院の魔剣使い10月アニメ放送 (@shimizuMFJ) November 27, 2018
https://twitter.com/610_cos/status/1067562776841740288
11月28日。#いいニーハイの日 #真島なおみ(@naomi_majima)#画像拝借 pic.twitter.com/4fM0Tbd7OX
— kan-suke(かんすけ) (@KSR621) November 27, 2018
https://twitter.com/SEGA_OFFICIAL/status/1067591230731694081
https://twitter.com/bakamusukokun/status/1067510092969345024
https://twitter.com/hinakonote/status/1067433963956760577
https://twitter.com/EREA_Denpa/status/1067434043879223298
https://twitter.com/Seinyan_1104/status/1067453347148394496
カーディガン+ニーハイも見たかったよせんせい… #いいニーハイの日 pic.twitter.com/jvsZa8r5t7
— 框(キョウ) (@86apricotton) November 27, 2018
艦これの響ちゃんと島風!#いいニーハイの日 pic.twitter.com/uAjY5CW54P
— ふー@アカウント移動済!固ツイに移動先有り (@gako0103) November 27, 2018
https://twitter.com/tsuruse852/status/1067620871026528257
https://twitter.com/mai_kanojo_dori/status/1067433189122002945
いいニーハイの日☆ #いいニーハイの日 pic.twitter.com/60xaIBUfxV
— 藤真拓哉 (@fujimatakuya) November 28, 2018
https://twitter.com/Miuuu1216/status/1067433487714533377
https://twitter.com/rc_navy/status/1067568679250870272
https://twitter.com/aoi_takamura/status/1067558199044108288
ニーハイといえばこの方。
#いいニーハイの日 pic.twitter.com/YIux8TJT9w
— 【祝10万人突破!】邪神ちゃんドロップキック (@jashinchan_PJ) November 28, 2018
https://twitter.com/banko003/status/1067545879983226880
https://twitter.com/HoshizakiReita/status/1067555038367690753
https://twitter.com/rumre_sn/status/1067556749438119936
この日用(?)に置いてたバンギャ撮影の時のお写真です…( •ω• ) pic.twitter.com/bLrDRiJASA
— 玲。 (@reixx_1213) November 27, 2018
なんでもない子JK~ポニ子~
今日ってか明日ってかもうすぐなんだけど・・・#いいニーハイの日ネコニーハイ! pic.twitter.com/XxD85g4FAf
— 保村 成(ほむらみのり) (@izumochi01) November 27, 2018
https://twitter.com/sacanahen/status/1067584734455226369
ニーハイの日と聞いて。#いいニーハイの日 pic.twitter.com/nKZqVgWUB8
— 水ようかん (@kuroan001) November 28, 2018
https://twitter.com/Ely_eee/status/1067674240353062912
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https://twitter.com/pck_ken_zaki/status/1067615090176749568
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https://twitter.com/Kururu_45/status/1067459079243624448