The A-type mask was used for the first 13 episodes.
The B-type for the next 16 episodes.
The C-type for the last 10 episodes.
The B-type is proud of the longest exposure.
The biggest enigma is why the B-type was changed to the C-type.
It should not have been necessary to change the mask.
Akira Sasaki says he does not remember why.
Toru Narita said when he was alive he does not understand the difference between the B-type and the C-type.
His remark is very confusing.
As it was a long time ago,the truth is unknown.
Anyway,the C-type is the most standard Ultraman mask you can see these days even though, surprisingly, it was used only for the last 10 episodes.
The C-type mask has been duplicated and used for Ultraman downward up to now including Kaette-kita Ultraman (Returned Ultraman/1971-72 ).
The original C-type mask is beautiful in a different way from the B-type.
The mouth bigger than the B-type looks slightly smiling and the whole impression is gentle.
It may be suitable for a hero.
Some fans say the C-type is the most complete Ultraman.
I like the C-type mask,too.
But, even though it should be incomplete in shape, I love the B-type Ultraman, too.
Japanese may find beauty in something incomplete rather than complete.