Zen's seed of universality is due to the very fact of its unique Japaneseness (its simplicity, practicality and flexibility).
Zen must be understood from the inside, not from the outside. One must first attain intuition and then proceed to the study of all its objectified expressions.
Zen is such that everybody will feel sabotaged by the zen master and everyone will feel hurt by him. Everyone will feel he is disturbing their sleep. It is utterly thankless.
Zen is concerned with manifesting rather than defining. If one asks of a zen master 'what is egotism' the zen master may become irate, causing the asker to become embarrassed. 'That' he will then say, 'is egotism'.
Zen is, in contrast to pragmatism (which appeals to the usefulness of truth), something that aspires to the purposelessness of work and to not leaving any trace behind as one lives one's life.
Zen is concerned not in knowing nothing, but in the belief that to know is outside of all texts, of all documents.