well as smartphones and tablets, using near-field communication. Unlike previous models, the Tamagotchi 4U does not have infrared, which consequently caused it to sell rather poorly. Marriage and family The Mesutchi and Osutchi Tamagotchis were the first to introduce marriages and offspring, and the feature returned in the Plus/Connection and subsequent models. Two players with a male and female pet may link their toys and allow the pets to develop a friendship and fall in love. Once the pets have raised their relationship meter sufficiently, the pets may marry. The player can also choose to have their pet marry a random pet brought in by the "Matchmaker." Once married, the female will eventually produce two eggs, keeping one and leaving one with the male. Since the parent will automatically guide the baby's life, the only care it needs from the player is medicine in the case of sickness. After 24 hours has passed or the offspring evolves into a child the parent will leave, and the player is left to care for a new generation. This can continue for as long as the player manages to care for the pets. The Chou Jinsei Enjoy Tamagotchi also introduced the idea of character "families" or "groups." These "families" are a kind of classification for characters obtainable in the game, grouped mainly by appearance, though they are also associated with certain skills. A character of one group cannot grow into an adult of a different group, and if two pets of different groups marry and have an egg, the baby will be of the female's group. Tamagotchi M!X has a notable change to this feature; in this release, Tamagotchi offspring will share genetics from both of their parents. Other With the many different versions of the toy, there are other less common mechanics that influence the pet's growth, including but not limited to friendship with the player, varying types of skills, and career. The Chou Jinsei Enjoy Tamagotchi also introduced Skills, which can be built by playing certain games with the pet, or using certain toys or foods bought from the E-Tamago or in-game shops. Having certain skills can help the pet obtain a career, and if built up high enough, can unlock special characters. The Tamagotchi Pix has a camera installed, allowing the user to get a pet based on the skin tone and age of the face, it also allows the