「Slow progress under the Sun」that was a LONG DURATION of waiting and interminable for the women, but also meaning BRIEF, FOR THE TIME BEING, the proverbial SHORT-TERM and TEMPORARY use of a service provider or military comfort woman, that was much anticipated for a long time by the soldiers but over in a flash, just a temporary fix for the time being there and then wanting again.
　Military use of comfort women was not a Japanese invention, formerly…everyone did it: pirates, bandits, gangs, armies the world over…because they could. Then there is God Almighty's take on this matter, found in Deuteronomy 21:10 When you go to war…and you take captives, 11 if you notice among the captives a beautiful woman and are attracted to her, you may take her as your wife. 12 Bring her into your home…then you may go to her and be her husband and she shall be your wife. 14 If you are not pleased with her, let her go wherever she wishes. You must not sell her or treat her as a slave, since you have dishonored her. See this researcher's website blog and well-documented published material to learn about the relationship between Japan and Korea prior to WWII, who it was that actually recruited Korean women as army service providers (in nearly all cases), and who is behind why this issue remains a propaganda flashpoint today:
　「I first confronted the comfort women issue in 1991. It was near the end of my study in Japan. As a volunteer I was translating former Korean comfort women's testimonies for NHK. When I returned to South Korea, the nationalism was out of control. The anti-Japanese activist group 'Korean Council for the Women Drafted for Military Sexual Slavery' (also known as Chong Dae Hyup 정대협 挺対協) was formed by the South Korean communists. Its leader said publicly it was determined to defame Japan for the next 200 years. Its propaganda turned me off, so I stayed away from this issue for years. I regained my interest in this issue in the early 2000s when I heard that Chong Dae Hyup was confining surviving women in a nursing home called House of Nanumu. The only time these women were allowed to talk to outsiders was when Chong Dae Hyup needed them to testify for the UN Special Rapporteur or the U.S. politicians. But for some reason I was allowed to talk to them one day in 2003. I could sense that women were not happy being confined in this place. One of the women (Bae Chun-hee) told me she reminisced the romance she had with a Japanese soldier. She said she hated her father who sold her. She also told me that women there didn't appreciate being coached by Chong Dae Hyup to give false testimonies but had to obey Chong Dae Hyup's order. When Japan offered compensation through Asian Women's Fund in 1995, 61 former Korean comfort women defied Chong Dae Hyup's order and accepted compensation. Those 61 women were vilified as traitors. Their names and addresses were published in newspapers as prostitutes, and they had to live the rest of their lives in disgrace. So the rest of the women were terrified of Chong Dae Hyup and wouldn't dare to defy again. Chong Dae Hyup (some of its members were arrested as North Korean spies) has used the comfort women issue for its political purpose, which is to drive a wedge into U.S.-Japan-South Korea security partnership.」
　　[　https://scholarsinenglish.blogspot.jp/2014/10/summary-of-professor-park-yuhas-book.html 2017-08-03　]
　Or, do you believe the North Koreans?　
　「Beheading day」as the BRIEF TIME it seems humans have to live.
　As a mnemonic perhaps, depicts a common pastime and ancient sport of kings and the nobility to spend some time during a warm afternoon (「sun, day」) with nothing better to do, killing time as it were, by grabbing ahold of a nearby pissant serf and then beheading by repeatedly rolling over the person's neck, slowly and gradually「chopping」using the「wheels」of the royal chariot to sever the screaming head. As you can imagine, sometimes this activity is over in a brief moment (well, perhaps just the screaming), but it may continue, dragging on for some time, vague as to duration, much to the delight of the passengers…sometimes moments seem to drag on for hours, particularly the unpleasant ones for a torture victim. In any case, it was deemed a pleasant way to spend some part of an afternoon, giving a nobleman something to do for a while, BRIEFLY, FOR THE TIME BEING, with these two perspectives different and removed from each other obviously, depending upon whether one was sitting in the carriage or rolling in the dirt.

Modern definitions (that generally disregard history) …excluding politically incorrect concepts and other meanings deemed offensive today; may list only pigeonholed definitions, euphemisms, or meaningless mnemonics)
Chinese: temporary
Japanese: little while, short while, moment, instant, a while, quite a time, it's been a long time, for a short while, for a brief period, after a short time, presently
Unihan extended: temporary
EDRDG: temporarily; a while; moment; long time