EZ Ching (4d4)

This method, using four 4-sided dice, was devised and made available commercially by Christopher and Avonne Thomson. These dice are no longer available on the internet but there is still a mention of them on Amazon. The original site (www.ezching.com) seems to have disappeard between 2008 and 2010 (according to the Way Back machine).
The four dice were, supposedly, hand made and were engraved so that for each group (yellow or blue) the eight trigrams appeared exactly onc.

They were used as follows:

1. Throw the four dice;
2. Pick the blue dice for the lower trigram;
3. Pick the yellow dice for the upper trigram;

This method generates each hexagram with probability 1/64.

To add changing lines it was suggested to use a regular die (1d6) to identify the moving line.

You can also use these dice to generate an hexagram and then derive a single line as described in the I Ching Book method.