Pokétch
The Pokémon Watch (Japanese: ポケモンウォッチ), or Pokétch (Japanese: ポケッチ) for short, is the navigational item present in Pokémon Diamond and Pearl, much like the PokéGear and PokéNav before it.
The Pokétch has 25 functions, including a map of Sinnoh like its counterparts did for Kanto, Johto, and Hoenn. It also has many functions that are not available at the start but can be recieved at a later time, and a few that must be obtained by showing a certain species of Pokémon to another character.
Functions
Watch
As its most basic feature, the Pokétch will display the time of day, much like the PokéGear of Johto had, only this time running in 24-hour format, instead of 12-hour AM/PM format. It runs off of the Nintendo DS's internal clock, and through this, can keep track of the date of a Pokémon's capture as well as the time of day. There are two different watch functions, one analog and one digital, though only the digital version is available from the beginning.The analog one is found in a house in Celestic town
Type matchup chart
This function will allow a trainer to choose the type of attack and the type(s) of the opponent Pokémon to determine whether a move is super effective, normal, not very effective, or ineffective against an opponent.
Breeding center monitor
Unlike previous generations, where trainers would need to stick around the breeding centers to make sure that they got their Pokémon egg as soon as it was ready, the Pokétch allows trainers to see the levels, genders, and species of the Pokémon located in the center, and will show whether or not an egg has yet been produced.
Calculator
The Pokétch also has a basic calculator, with addition, subtraction, multiplication, and division functions usable. It is able to display up to ten digits. It is one of the applications available from the beginning.
Step counter
This device allows trainers to count the amount of steps taken, a value that often determines things, such as out-of-battle poison damage, egg hatching, and Safari Zone excursions. It is also instrumental in obtaining the Surf glitch. It is one of the applications available from the beginning.
Drawing pad
A notepad for trainers to use as they walk the field, for writing notes on the area or notes on which Pokémon to get to beat the next gym. Unlocked after defeating Roark and visiting the Pokétch building.
Party status
This shows the most basic stats of the Pokémon that the trainer has with them: HP level, species, and whether or not they are holding an item. It is one of the applications available from the beginning.
Party tameness
Shows the tameness of the various Pokémon in the party. Obtained at Eterna City's Pokémon Center.
Itemfinder
Finds items located on the top screen of the DS when touched. Receive from Dawn/Lucas upon arriving on Route 207.
Berry map
A map of Sinnoh showing where mature berry trees are located in the region.
Recently-obtained Pokémon
Shows the twelve most recent Pokémon captured, evolved, hatched, or traded into the game.
Counter
Counts anything players choose to; upon press of the bottom screen, the number goes up by one.
Map of Sinnoh
The version of the Town Map for the Sinnoh region. Allows players to place different markings on locations to show them as destinations, as well as the locations of the two Pokémon that travel around Sinnoh, Cresselia and Mesprit, much like Entei, Raikou, and Suicune travelled Johto and Kanto and Latios and Latias travelled Hoenn.
Wireless activities
Allows interaction with other players using the functions nearby.
Coin flip
Players can flip a coin.
Pokéradar
Shows the three longest streaks of Pokémon seen by the player.
Calendar
Shows the current month and day.
Drawing/puzzle board
Strange scratch-off/doodle board.
Roulette
Spins. Start and stop are controlled by the player.
Egg timer
Timer with an alarm.
Color modifier
Changes background color of the Pokétch.
Matchup checker
Checks whether two party Pokémon are compatible to breed.
Stopwatch
Reverse of the egg timer, counts up instead of down.
Alarm clock
Sets an alarm to ring at a certain time.