Another episode that I've recently seen is the one for a 1948 song composed by Koseki, "Francesca no Kane" (The Bells of Francesca). Kazuo Kikuta（菊田一夫）was the lyricist for this particular kayo which dealt with a woman experiencing a variety of emotions such as shock, rage and mourning since he was losing the man that he loved to a higher power. He was breaking things off because he was entering the monastery. "Francesca no Kane" is the musical equivalent of that bitter pill to swallow as Akiko Futaba（二葉あき子）sadly relays the woman's feelings. There was also a spoken verse provided by actress Taeko Takasugi（高杉妙子）, the wife of lyricist Kikuta, who effectively spat out her mocking disdain for her soon-to-be former beau while undergoing what sounded like delusional denial about her plight.
Through the J-Wiki article on "Francesca no Kane" with the original sources being a 1980 autobiography about Koseki and a 2019 book on the songwriter called "Koseki Yuuji ~ Ryuukou Sakyokuka to Gekidou Showa"（古関裕而～流行作曲家と激動昭和...The Popular Composer and The Turbulent Showa Era）, I got one answer on my question on "Who was Francesca?". Apparently, Koseki asked Kikuta about the name, assuming that it was the monastery where the young man was heading for. The lyricist simply replied that he had no idea; he picked the name because he liked the sound of it!
The J-Wiki article also mentioned that singers such as Kenji Sawada（沢田研二）and Tokiko Kato（加藤登紀子）have covered it. I managed to find Julie's performance above, and it's definitely more of a sultry and sullen rock thing here. Unfortunately, I haven't been able to track down Kato's cover of the song but there is Kenichi Mikawa's（美川憲一）jazzy Mood Kayo take on "Francesca no Kane".