Pokémon GO will host its Replay: Riolu Hatch Day event on April 18 from 11 a.m. to 5 p.m. local time, giving trainers a focused window to hatch Riolu from 2 km Eggs. During the event, Riolu will appear much more frequently and players will have an increased chance of encountering Shiny Riolu. The short, time-limited event is designed to get players out exploring and hatching, while providing a rare opportunity to add this popular Pokémon to their collection. Fans of Riolu and shiny hunters alike will likely be logging on to make the most of the event.
Source: Official Pokémon GO blog
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