English: The single vertical line means authority, power, or dominance. The three horizontal lines together is an established ideogram. In one system of psychological signs the three horizontal lines symbol is used to mean 'passive intellect', which is synonymous with submissive.
Comment: The "passive intellect" symbolism of three parallel horizontal lines is taken from Rudolf Koch's The Book of Signs, and is (somewhat confusingly) almost exactly opposite in meaning to the symbolism of three parallel horizontal lines in the Chinese "I-Ching" trigram system...
http://www.masterslaveflag.com/html/faq_s.html (flag design)
Own work (vector conversion)
Master Tallen (flag design)
私の名前は信じられないほどの名前です (vector conversion)