I saw someone selling these two oddball NPB cards on Ebay a few weeks ago and I couldn't resist picking them up. They're not something I'd ever seen before and I don't believe they're in Engel's catalog although I may have missed them.
The first card is labeled "Central League 2nd Basemen". The top row is Toshiyuki Mimura (#9 of the Carp), Morimichi Takagi (#1 from the Dragons) and Katsuhiro Nakamura (#14 of the Tigers) while the bottom row is Mitsuyoshi Masukawa (#48 of the Swallows), John Sipin (#11 of the Whales) and Takeshi Ueda (#2 of the Giants).
The other card is labeled "Pacific League Outfielders". The top row has Yutaka Fukumoto (#7 of the Braves), Kyosuke Sasaki (#5 of the Buffaloes) and Masahiro Doi (#3 of the Lions) with the bottom row having Sumio Hirota (#3 of the Orions), Hiromitsu Kadota (#27 of the Hawks) and Junzo Uchida (#7 of the Fighters).
I've pretty much narrowed the set down to most likely being from 1975. It can't be any earlier than that since that was the first year that Doi was with the Lions and Uchida was with the Fighters. It's unlikely it's from later than 1975 because 1975 was the last year that Masukawa (who never actually played second base for Yakult) wore #48.
These were advertised on Ebay as cards but now that I have them in hand I can see that they are actually stickers. Each photo can be peeled off the sheet as well as the team flags on the bottom.
I don't know anything else about these but I assume that there are more of these for other positions. I'd be interested in finding out more about these.