Secret vehicle

the secret vehicle, it is not suitable to be brought within lesser scopes of immature disciples because it is dangerous vehicle,

because of respect and caution, it directly leads to 3 kayas of Buddhahood but in two-way travel with no sidetracks whether it go up straight to Enlightenment or if profaned down to the most miserable state,

one need at least strictly cultivate suitable tantric or Bodhisattva vows and properly rely on Vajra-master, there is very easy for misunderstanding of vajra-expressions because not to be aware of various 6 alternatives and 4 modes of the meaning.