Kaeru no Tame ni Kane wa Naru
September 4, 1992
This game features some similarities to Zelda games, the most immediate being the over-head view and hearts for life, but there also are the bottles used as containers for life-restoring potions, like in A Link to the Past, and hidden caves where the player can find Old Men to obtain extra items, like in the original The Legend of Zelda, however these may be too general game features to be considered references. The only stronger reference to the Zelda series is a forest consisting in a cross-section in which all paths lead back to it and can only be surpassed by follow a specific pattern through it, therefore funcioning exactly like the Lost Woods in The Legend of Zelda (however the pattern is different).
The Legend of Zelda: Link's Awakening
June 6, 1993
This game uses the same engine as Kaeru no Tame ni Kane wa Naru, in fact a graphic similarity can be noted.
Prince Richard from said game even makes an appearance: he's found in a small house, Richard's Villa, which is filled with frogs, referencing his game's theme. He says that he once lived in Kanalet Castle, but was kicked out by his rebellious servants, leaving hes precious Golden Leaves behind. After Link retrives all Golden Leaves from thecastle, he rewards him by granting access to the Pothole Field, the garden in back of his house.
Notably, both Richard's and the frogs sprites are taken directly from Kaeru no Tame ni Kane wa Naru, and the music that plays in Richard's Villa is a remix of the overworld theme from that game. Notably, after looping for 2 minutes and 30 seconds, the song momentarly changes to Totaka's Song, the signature tune by composer Kazumi Totaka, hidden in most games he worked on.
This cameo was left in the Game Boy Color remake Link's Awakening DX, where is also possible to get a picture for the photo album by walking up to the main gate of Kanalet Castle before it is opened.
Copyrights for both series are held by Nintendo.