japanese_become_shogun_reward_effect

japanese_become_shogun_reward_effect = {
	# Setup
	japan_clear_flavour_flags_effect = yes
	set_global_variable = {
		name = shogunate_established
		value = yes
	}
	add_character_flag = shogun_flag

	# Rewards
	if = {
		limit = { has_dlc_feature = legends }
		create_legend_seed = {
			type = legitimizing
			quality = illustrious
			chronicle = great_deed_dynasty
			properties = {
				dynasty = root.dynasty
				founder = root
				title = primary_title
			}
		}
	}
	add_dread = massive_dread_gain
	add_legitimacy = monumental_legitimacy_gain
	add_realm_law = japanese_bureaucracy_1
	dynasty = { add_dynasty_prestige = monumental_dynasty_prestige_gain }
	culture = {
		if = {
			limit = { has_cultural_tradition = tradition_tgp_imperial_peace }
			custom_tooltip = {
				text = tradition_tgp_bushido_tt
				remove_culture_tradition = tradition_tgp_imperial_peace
				add_culture_tradition = tradition_tgp_bushido
			}
		}
		else = { custom_tooltip = unlocks_bushido_tradition_tooltip }
	}
	every_culture_global = {
		limit = {
			has_cultural_tradition = tradition_tgp_imperial_peace
			OR = {
				has_cultural_pillar = heritage_japonic
				culture_head ?= { government_is_japanese_trigger = yes }
			}
		}
		custom_tooltip = {
			text = tradition_tgp_bushido_tt
			remove_culture_tradition = tradition_tgp_imperial_peace
			add_culture_tradition = tradition_tgp_bushido
		}
	}
	every_vassal = {
		custom = every_japan_admin_vassal_custom_bullet
		limit = {
			government_has_flag = government_is_japan_administrative
		}
		show_as_tooltip = { change_government = japan_feudal_government }
	}
}

As written in game/common/scripted_effects/10_dlc_tgp_japan_scripted_effects.txt.