Sri Lankan curries need spices, coconut milk and a few special flavors. Japan has a surprising match for one of them: katsuobushi is very close to Maldive fish.
The spice aisle of large supermarkets has curry powder, cinnamon and mustard seeds. KALDI and Gyomu Super sell coconut milk and basmati rice. Indian and Sri Lankan shops, and online shops, sell roasted curry powder, curry leaves and goraka.
Roasted curry powder
Sri Lankan shops, online
If not: Curry powder dry-roasted in a pan until dark and fragrant
Maldive fish
Sri Lankan shops
If not: Katsuobushi (ใใคใ็ฏ), crushed
Curry leaves (ใซใฌใผใชใผใ)
Online, some Indian shops
If not: A bay leaf (ใญใผใชใจ); the aroma is different but it helps
Pandan (rampe)
Online, Asian shops
If not: Leave it out
Goraka
Sri Lankan shops
If not: Tamarind or a little lemon juice
Coconut milk (ใณใณใใใใใซใฏ)
Ethnic shelf; cheapest at Gyomu Super
Ceylon cinnamon (ใทใใขใณในใใฃใใฏ)
Spice aisle
Mustard seeds (ใในใฟใผใใทใผใ)
Spice aisle at large supermarkets, KALDI
Red rice
Online
If not: Japanese brown rice (็็ฑณ) or basmati
Lazy Recipe sees that you're in Japan, picks swaps from Japanese supermarkets, and your shopping list shows each item's Japanese label and aisle. Type a dish or snap a photo.