The Mesutchi and Osutchi (Mesu meaning girl, and Osu meaning boy) are a collective Tamagotchi release that debuted August 1997. The Mesutchi and Osutchi were the first Tamagotchi releases that introduced the concept of breeding, and were the first Tamagotchi release to have a total of 10 icons rather than 8.
The Mesutchi and Osutchi were both larger than the original Tamagotchi pets, the same size as modern Tamagotchi virtual pets. The top features a removable cap that was used to interlock two pets.
Three designs were released, as well as a special collector's edition to celebrate the first anniversary of Tamagotchi.
The Mesutchi and Osutchi included all of the normal Tamagotchi functions, though introduced several new ones.
The game on the Mesutchi and Osutchi was called "Flag". Similar to the same game used on Tamagotchi Connection Version 3 and V4, though much simpler, players has to watch their Tamagotchi hold up 2 flags, and press the button under the corresponding flag. For example, when the Tamagotchi held up the black flag, the player would press B. There were 5 turns, and getting 3 or more is considered a win.
The Mesutchi and Osutchi had a removable top section of their shells, and inside held two small, square conductors. When the Mesutchi and Osutchi were adults, players could interlock the two pets, then make them breed and have babies. Unlike modern Tamagotchi releases, the gender of the baby was based only on if they were on the Mesutchi or Osutchi rather than the baby's color.
The TMP was located as the 8th icon, and appeared as a smiling face wearing a crown. It told what family the character was in and what generation it had grown to. According to the Japanese instruction sheet included with each Mesutchi / Osutchi, TMP stands for Tamagotchi Mating Power.
- Adult (Mesutchi)
- Adult (Osutchi)