Keeping Kosher, Halal, or strictly vegetarian can be ridiculously difficult abroad, especially in a country where your dietary restriction is not widely held. Usually dietary restrictions are accompanied by personal thresholds, ranging from a zero tolerance policy to (for example) “just as long as I don’t actually eat a hunk of meat.” This post is geared mostly for those who are on the stricter parts of the spectrum, either for allergies or religious reasons.
1. Finding Allergens
While the back of packaging will always have a list of ingredients (in Kanji), most Japanese prepared foods do not label wheat, peanuts, tree nuts, shellfish, or citrus fruits with special indicators or pictures. Helpful allergen charts like on the CheeseRich line of snack packs are also in Kanji, though easier to search through than the basic ingredient （原材料名）list on the back.
Here are some Kanji to look out for:
落花生(らっかせい) or 南京豆 (なんきんまめ) : Peanut
胡桃 くるみ ： Walnut
海老 （えび) : Shrimp
帆立 (ほたて) : Scallop
貝 （かい）: Shellfish
麩質 (ふしつ): Gluten
小麦 （こむぎ）； Wheat
柑橘類 (かんきつるい): Citrus Fruits
If your allergies are severe, you can look for this sentence:
It has the same connotation as “this product is made in a factory that uses (allergen).”
2. Finding Pork Products (豚肉）
No major or well-represented religion in Japan has an express restriction on pork. (Strict Buddhists are often just straight up vegetarian or vegan.) As such, food products that were Kosher, Halal, or even vegetarian in countries with populations that keep Kosher and Halal are, fairly often, cooked with pork products. Unless you are always in the habit of looking, this could lead to an unpleasant surprise. Most curry rice cubes and several bakeries use pork extract and lard, respectively. With curry, if you have a zero-tolerance policy, you might need to skip the cubes and buy powder mixes, which are only spices and allow you to use your own oil and extracts.
Lard is rarely written in katakana, and has its own kanji, 脂, that shares a reading with vegetable oil, あぶら (油). Asking “is there lard in this?” (あぶらがはいていますか) could very easily be interpreted as “is there any type of oil in this?”, a tragic misunderstanding that would rule out a lot of delicious things in your life. Instead, if at a bakery, you can ask if the oil is 植物油 （しょくぶつゆ）. Also you can ask if there are pork products 豚から製品 or ぶたからせいひん in your object of choice.
Best of luck!
Lauren is an ALT in Komatsu who has yet to find a pork-free curry cube.