This page explains in detail the interactions between the Tetris series and the Yoshi series.
An interaction between the Tetris series and the Panel de Pon series is also included at the Tetris Attack section.
Tetris Attack[]
August 1996
Panel de Pon and Yoshi
Tetris
Cover of the game.
This game, called Yoshi no Panepon in Japan, is a crossover between the Panel de Pon and the Yoshi series but it received the title Tetris Attack upon its western release.
Beside changing the title, the western release also features a completely different cover art, focusing exclusively on the game's tiles and angry garbage tiles, somewhat hiding the Yoshi theme of the game.
It should be noted that the western release actually predates the Japanese one by a couple of months: Tetris Attack was released for SNES and Game Boy in the North America in August 1996, then Yohi no Panepon was released for Game Boy in October 1996 in Japan, and then for Super Famicom through Satellaview in November 1996.
These however are close enough that we can assume development and localization of the game to have happened simultaneously.
While many consider Tetris Attack just an odd entry in the Tetris series, because the game itself has nothing to do with Tetris we consider it only a Panel de Pon - Yoshi game, and the "Tetris Attack" name is only a commercial move to appeal to the western audience creating an out-universe link.
In a 2009 interview, the CEO of the Tetris Company said about this game that "it’s not Tetris", so that can sort of be considered the official stance as well.
Tetris DS[]
March 20, 2006
Tetris
Yoshi
Tetris DS features six different modes, each one with themes from a different Nintendo game, and Puzzle Mode is the Yoshi's Cookie-themed mode (For details about other modes see Nintendo X Tetris#Tetris DS). This mode presents the player with various situations and the player must solve them selecting the right tetrominos in the right order. The top screen reproduces Yoshi's Cookie game screen, with the playfield on the left, with Cookies going trough pipes around it, Chef Mario in the upper left section, while the bottom left section has the cookie count replaced by two Yoshis holding a sign telling how many tetrominos must be used. The bottom screen shows the selectable Tetrominos and has the cover art for the Japanese version of Yoshi's Cookie as the background. This image is edited to have Yoshi look at the camera, rather than in front of him.
Notably, the Yoshi series is the only one to be represented in a game mode, but not in a level in Standard Mode.
License[]
For the western release of Tetris Attack, Nintendo simply licensed from the Tetris Company the right to use Tetris' name.
In a 2009 interview, the CEO of the Tetris Company expressed regret in granting the license for a game unrelated to Tetris, and that's possibly why later Panel de Pon games were released in the west with the title "Puzzle League", and also why Tetris Attack was never released for Virtual Console in the west.
Tetris DS was produced by Nintendo, so they could freely include characters from their series in it.