Chieko is currently listed with a Japanese talent agency, with a photo that looks like it was taken within the last few years, but her inclusion on their roster is most likely just to boost their status. According to her Japanese Wikipedia entry and one other source, the 5'6" 34-23-35 former "V Cinema" queen retired from show biz in early 2000 and is now living a domestic life with a husband and son.
Sounds likely but until that's reliably confirmed or unless she one day (hopefully) makes a comeback, I'm afraid Chieko will continue to reside in the "Whatever Happened to..?" file and in our memories. So, the following is a little trip down memory lane.