You only need the sigil during definition. So, for example (in the Perl 6 REPL):
> my \x = 1
1
> my \y = 2
2
> say "Look Ma, no punctuation!" if x + y == 3
Look Ma, no punctuation!
There are some implications of this; namely: x and y are now immutable. Back in the REPL:
> my \x = 1
1
> x = 2
Cannot modify an immutable Int (1)
in block <unit> at <unknown file> line 1
This is because in Perl6 the sigil is a container for the value represented by that variable, so since you don't have a sigil, you don't have a container; that is: the names "x" and "y" are now literal synonyms for "1" and "2" (respectively). "x = 2" fails here for the same exact reason (and with the same exact error message) you'd get if you tried to do "1 = 2".
For those interested on learning more about containers in Raku, lizmat wrote a nice article about them [1]. There's also this documentation page [2] that gives a detailed overview of them, where you can find more about sigilless variables.
