Dear Khalsa Ji,
Dasham Dwar is not a physical opening like the other nine openings in human body. It is a a path way to link up with 'The Sat', it is a state of being. When one resonates with 'Shabad' i.e. when the individual has incorporated the teachings of the 'Siri
Guru Granth Sahib' in her or his being, then the individual stands linked with 'The Sat'. This is a state of being. As we all know 'The Sat' is nirakaar, 'The Sat' does not need a physical entrance i.e. dwar. Hence one should not think that it is a physical opening that has to be found.
Dasam Dwar is a state of being in which the individual stands linked with 'The Sat'.
With love and respect for all.
Amarpal Singh