2月10日は「左利きグッズの日」だったけれど*1、それよりもかなり前から8月13日は「左利きの日」だったんだね*2。1992年に英国の「左利き倶楽部」*3という団体が始めた。
See al.so
On 13th August 1992 the Club launched International Left-Handers Day, an annual event when left-handers everywhere can celebrate their sinistrality and increase public awareness of the advantages and disadvantages of being left-handed. This event is now celebrated worldwide, and in the U.K. alone there were over 20 regional events to mark the day in 2001- including left-v-right sports matches, a left-handed tea party, pubs using left-handed corkscrews where patrons drank and played pub games with the left hand only, and nationwide “Lefty Zones” where left-handers creativity, adaptability and sporting prowess were celebrated, whilst right-handers were encouraged to try out everyday left-handed objects to see just how awkward it can feel using the wrong equipment!
http://www.lefthandersclub.org/left-handers-day.html
ハフポスト日本版編集部「左利きの日。左利きの“最大の天敵”は意外なアレだった。」https://www.huffingtonpost.jp/2018/08/12/left-hand-day_a_23500939/