The preparation for down block gedanbarai can be found in each of the Heian Katas. Here is a basic application using the preparation for down block as the primary blocking technique in each of the Heian katas.
There are many people who started their karate training in the last 5 to 8 years who only know competition sport karate. These sport karate competitors have only been taught sport karate style katas. Very fast movement, long drawn out pauses. Robotic transitions and not showing any fight or bunki in the kata. When they see a kata not done in this (sport competition) manner they think there is something wrong with the way the kata was performed. It's simply doing Kata in the Dojo.
Think of Kata as self-defense against one or two opponents Think of each individual movement of kata as a singular fighting technique, that may draw from the previous movement or help set up the next movement.
Know that techniques change principles do not change