After completing “Gazing Three Thousand Miles Away” from Chouji, you can still find him in front of his house near Jakotsu Mine, Yashiori Island. This is actually part of hidden achievement: And I Would Walk 3,000 More.
First, talk to him and he will tell traveler about his plan to look for him mother. in this phase, you will need to give him 12 Crystal Marrow.
Second, met and talk to him in Tatarasuna as shown in the map.
Third, met and talk to him in front of big red shrine in Narukami Island as shown in the map. This is the last part and you will get Precious Chest as reward.