Released in August 1, 1983, this song (*together with "Glass no Ringo", will be explained later) reached #1 in Oricon chart with 857,390 sales.  It was also ranked #1 in Oricon monthly chart of August 1983, then #6 in September montly chart, and then #3 in both October and November monthly chart. At the end of the year, this song was ranked #7 in Oricon yearly chart of 1983 (*7th highest selling song of that year). This song is Matsuda Seiko highest selling song in 1980s and her second highest selling song in her entire career.

When it was released in August 1983, this song was B-side song of "Glass no Ringo". But it got very good reception from the fans (maybe even more than the A-side / main song), and got even more popular after it was used as soundtrack for Suntory beer commercial. They quickly re-released it in October as double A-side song.

*A-side? B-side? Double A-side??

An album usually contains 8-12 songs in a CD / cassette / vinyl record, while a "single" only has two song: A-side song (the main song, the main attraction, the main reason people buy that CD, the song the singer will promote the most and sing it in all kind of music programs) and B-side song (a bonus song, the singer will probably sing it once or twice on TV if at all). To promote a song, they need a lot of resources (money, time, energy, etc), so they can't just waste it on any random song but to focus it on the song they think will sell the best: the A-side song. Double A-side song means both songs are treated as the main songs, both will be promoted and performed on TV equally. So which song sold 857k copies, "Sweet Memories" or "Glass no Ringo"? Both, since they're two in one, two songs counted as one since they are in the same CD. 

This single won 4 awards, including "Japan Song Awards" and a gold in "Japan Record Awards". "Glass no Ringo" has been covered by 6 singers (1991 - 2020) while "Sweet Memories" has been covered by 47 singers (1984 - 2021). Seiko sang "Glass no Ringo" in Kohaku Uta Gassen 1983 and "Sweet Memories" in Kohaku Uta Gassen 1999. 

"Sweet Memories" is Seiko's masterpiece. More importantly, this is Seiko personal favorite song. 

This song was used in Suntory beer commercial:

^ the penguin looks so pitiful, it makes you wanna cry. That penguin got her own anime movie a few years later.

Now, feel her "queen" aura....

Her live performances:

^ in "Yoru no Hit Studio"

https://www.bilibili.com/video/BV1W4411S7Hd

^ in "The Best Ten" that had their own ranking system, this song also reached #1. 

^ in "The Top Ten" (before they changed its name into "Uta no Top Ten") that had their own ranking system, this song was ranked #1

^ in "The Top Ten" again

^ also in "The Top Ten" (mixed with footage from "Super Jockey")

^ this too was in "The Top Ten". Full video: https://www.bilibili.com/video/BV1UX4y1B7La

^ in "Let's Go Idol"

in other music programs:

in late 1980s

in an epic moment in 1990 (all biggest 1980s idols (except Kyon2, Matchy, Toshi) gathered in the same show. The dream team!)

https://www.bilibili.com/video/BV1sM4116789

^ the other "queen" was clapping for her and singing along from her seat. Moritaka Chisato, B.B Queen (+ Mi-Ke) and Hikaru Genji were watching her. Wink, Kudo Shizuka and Nakayama Miho were preparing for their turns to perform, but probably also watched Seiko from their dressing rooms.

in 1994 (11 years later)

duet version with Saijo Hideki (1970s male idol)

https://www.bilibili.com/video/BV1YW41137vD

This song has been re-recorded many times through the decades.

In 2010, Suntory beer recreated the penguin commercial, now in live action

^ the penguin had turned into the beautiful Seiko.

The newest version from 2020:

^ the "queen"!! The "eternal idol"!!

It was still used as commercial soundtrack for McDonald in 2020