Six ways of expounding the inner tantras; as mentioned in the rgyud gal po che: (1) According to the conventional meaning /truth (drang don), (2) Ultimate certain meaning /truth (nges don), (3) With a hidden meaning behind intelligible words which have an ordinary meaning (dgongs pa can), (4) In a explicit way, without hidden meaning (dgongs min), (5) In ordinary words of common language (sgra ji bzhin pa), and (6) in symbolic words arranged in sentences which makes no sense without a key for their understanding (sgra ji bzhin ma yin pa)