Kaki no tane are small banana shaped Senbei which are hollow and have a crunchy bite with a bit soy flavor. This snack is often eaten when drinking alcohol and thus a popular bar snack. In the supermarket you can find really big bags just full of Kaki no tane. Regular snack packs are also common, for the “oyatsu” (snack) time at work or home. Here the Kaki no tane is often mixed with peanuts, and this is simple called Kaki Pi. These also come in different flavours such as wasabi and plum.
Translating Kaki no tane to English gives “seed of the Kaki”, and that is exactly what this snack looks like hence the name. Kaki is a Japanese fruit (persimmon in English) similar to orange, having a bit sharper taste though.