I-Ching: Book of Changes is a free Android app developed by Bondia Tecnologia that offers a comprehensive study and oracular consultation of the I-Ching. The app includes a full translation of the I-Ching into Portuguese and English, as well as a reference guide for the oracle and full trigram/hexagram information, including changing lines. It also allows users to store and take notes for their consultations, and generates related hexagrams where applicable.

In addition to the oracular consultation features, I-Ching: Book of Changes includes introductory information on the basics of the I-Ching, structured references of all trigrams and hexagrams with useful search features, and offline functionality that does not require an internet connection. The algorithm of randomness used in the app is based on the method of rods, which means that mutable yin and yang occurrences are not equal, resulting in a low occurrence of yin mutable lines. The app is designed by geeks who love zeros and ones, ensuring a user-friendly experience.

Overall, I-Ching: Book of Changes is an excellent choice for anyone interested in studying and consulting the oracle of the I-Ching. The app is easy to use and offers a wealth of information in a convenient and accessible format.