Tanpopo (タンポポ dandelion) was the first official subgroup of J-Pop girl group Morning Musume. They sang slow and mature songs and, eventually, the style of their songs changed. As with all things J-Pop their lineup changed over the years, and ended with fifth lineup of the group in 2002 before they went on an indefinate hiatus. But looking back to the good old days, here is a super cute commercial for "Koi wo Shichaimashita!" which came out in early 2001:
Here's a series of two commercials for "Oujisama to Yuki no Yoru" which came out in late 2001: