Korintje cassia is an Indonesian cinnamon. Fragrant and smooth, the style closest to that sold in supermarkets, but much fresher and of superior quality. This is the style of cinnamon that speciality cinnamon-bun bakers favor, for its rich sweetness. Korintje cinnamon is a bit milder than China cinnamon, and so has been favored for blending with other spices for sweet spice cakes, coffee cakes and fruit pies.
I order my cinnamon from Penzeys Spices.