There is many gluten free curry options at the grocery store you can easily find. I decided to make a short list with the one I have seen the most in my nearby grocery stores.
Instant (Add to boiling water along with meat and vegetables)
Family size : I usually buy the three below because they are the only instant options I have found until now. My kids like particularly the one with apple, on the right. These can be found at MaxValue and Aruk, or on Amazon Japan with the below links. One box makes 6 adult potions.
Individual portions: The below are from another known brand called S&B. They are very good although only makes 2 portions per boxes so I usually end up buying quite a few. A great option for one adult. Available online below or at Max Value, Red Cabbage and Aruk.
Ready to Eat
Individual portions : If you feel like making the whole instant meal is too much work, there’s also a many ready-to-eat option made by S&B. Most of allergens curries are designed for children.