How do you get jirachi in shiny gold?

First of all,obtain 200 pokemon.You dont have to capture them all because it increases based on evolutions.For eg. when I obtained my starter Cyndaquil,the pokedex showed the number of Pokemon owned as 1.But a soon as it evolved,it became 2.Thus you can increase the number of Pokemon owned by evolving maximum Pokemon.After defeating the Pokemon League and receiving S.S. Ticket,you can go to Kanto.To the east of Fuchsia City,there is a large pillar.Go to that Pillar with an empty slot in your party,click the A button on that pillar and you will get an egg.It will take much time to hatch it.I used that time to Defeat the League 17 more times and also evolved a Pichu into a Pikachu and trained it upto level 53.So you can know how much time it takes.Jirachi hatches from that egg..:-)