well. New features As with other generations of Pokémon games, Diamond and Pearl retain the basic gameplay of their predecessors while introducing additional new features. The day-night cycle makes a return and has increased from three times of day in Gold and Silver to five time periods in Diamond and Pearl: morning, day, afternoon, evening, and night. Diamond and Pearl also introduce several changes to battle mechanics. In previous generations, Pokémon moves were classified as "physical" or "special" based on their type; for example, all Fire-type moves were special and all Ground-type moves were physical. In Diamond and Pearl, however, moves are categorized into three groups. Attacks that make physical contact with the opponent are "physical", attacks that do not make physical contact are "special", and moves that do not deal damage are classified as "status". Some of the games' new features capitalize on the Nintendo DS's features. The Pokétch, a simulated smartwatch, resides on the DS's bottom screen and hosts various applications including a clock, calculator, map, counter, and a drawing pad. These applications are obtained throughout the game. Beneath Sinnoh's surface is the Underground, a large area used for wireless multiplayer gaming; in it, players can create and decorate secret bases, first featured in Pokémon Ruby and Sapphire, and participate in minigames. The items mined in the Underground can then be transferred into the player's bag in the main game. Diamond and Pearl also employ support for the Nintendo Wi-Fi Connection (since discontinued), allowing players to communicate through voice chat, trade, and battle online. The main system for trade is the Global Trade Station, which allows players to trade with people around the world. Players can search for any Pokémon that they have seen in the game and can offer their own; if another player is offering the requested Pokémon and is looking for the offered Pokémon, the trade occurs immediately. A trade does not have to be instant; an offer can be left for other players to browse and complete, even while the player is offline. Certain species of Pokémon traded internationally will have a Pokédex entry in the language of the game it originated from. According to Pokémon art director Ken Sugimori, the Global Trade Station was the new feature he was most pleased with. Pokémon Contests are events in which the player's Pokémon compete in a show to win ribbons and, in Diamond and Pearl,