Here’s a little bit from the introduction of Mabuni and Nakasone’s “Karate-do Nyumon” that talks about Itosu Anko sensei.

Itosu Sensei & Imperial Rescript on Education 

Every day as usual on my way back from school I would go straight to Itosu sensei’s house to practice. One day I had a small scroll in my hand. Sensei looked at it and said, “What is that?”. I replied, “It’s the Imperial Rescript on Education.” And he said, “Let me see!” So, I gave him the scroll,” Sensei read the scroll with a solemn look, then wound it up and asked me if I would let him read it. So, I replied, “It would be my pleasure”. “Thank you, I’ll read it every day” he said and gave the scroll back to me. After that, Itosu sensei read Imperial Rescript every day as a part of his daily routine, but sometimes he would copy it. In my collaboration with my co-author Mr. Nakasone, I have decided to make public my dear teacher Itosu Yatsune sensei’s true style of Karate. However, it is my hope that those who want to learn about Itosu’s style do not simply learn the skeleton of kata but understand the deep significance behind his mental attitude. 

(Kenyu No. 2 [Friends of the Fist] No. 2) 

The Imperial Rescript on Education is controversial in some respects as it entrenched focus on the Emperor and Confucian ethics with an emphasis on filial piety. This Japan Times Article has an interesting analysis of it from a modern perspective.