fasm doesnt seem to accept

mov ax,es:[bx]

in 16 bit real programs,

eg see attached no-op program xyz.asm

I know this is correct asm as it is accepted by the
assembler I was using previously,

the hex dump of xyz.com via the previous assembler
is:

0000: BB000026 8B07B44C CD21

and it runs without problem doing nothing,

I want to be able to use non default segments otherwise
the coding can get very tricky trying to do everything via
implicit segment registers

I looked through the online documentation but couldnt
see this explained,

is there some directive to do this?

mov ax, [es:bx] will work

now why didnt I think of that!

I've tried now

mov eax,[es:ebx]

which also functions

I can continue with the code I'm working on,

I suppose [es:bx] is a more logical notation

(as es:[bx] literally means the segment :offset where
segment = es and offset = [bx], whereas [es:bx] means
the thing pointed to by es:bx )