Today, while exploring this site here, I found out that I confused the lines when using the 3-coins method about 15 years. Recently I start trying to understand the I-Ching in a deeper way.
A friend of me thaught me once how to use the coins, and he said: three times head is 6, three times tail is 9, two times head is 7 and two times tail is 8. I never questioned that -- At least, the system was consistent in itself
And what can I say, it worked out, or at least I believed in my results.
I am stunned that I did it wrong all the time. And I ask myself, how should I go on? With the method I learned, or with the 'right' method? I am a bit afraid, that I can't use it any longer the way I learned it, because I fear that it's wrong. But I also fear that I cannot simply change the system from now on.
Has anybody a clue? Thank you.

Best regards, blackmilk.

You didn't do it wrong. It doesn't matter which sides of the coin you assign values to as long as you are consistent.

Ah okay, thank you a lot. I found no site in the web, that did it like me

Who told you that's wrong? That's how I do it.
My collection has just about everything in print, as of eight years ago.
I did a survey of all of them and the recommended method was about half one and half the other.
The differences don't correlate with quality of scholarship either. So just be consistent.
When using Chinese coins, there seems to be a moderate preference for assigning the side of the coin with four characters the value of two, and the side with no or two characters the value of three, but there are still a lot of authors who say the opposite.

Thank you.

If this is helpful, I once attended a series of lectures by the (excellent and erudite) astrological scholar Geoffrey Cornelius who has written a great deal on the fact that 'wrong maps work' - by which he means, the phenomenon whereby inaccurate astrological charts (cast on 'wrong' data, wrong dates/times etc) still work. Rather than devaluing the practice and efficacy of divination, the premise is actually rather profound - more profound than I am able to articulate in this forum post, but perhaps you catch my vague drift...

Thank you so much for your thoughts.