Letter shifting is used to move single or multiple letters within a word to make a different word, or get letters into the correct position in part of the fodder that makes up the answer word. To help show this the setter will employ a letter shift indicator. Let's take a peek at some examples:
To make STATE become TASTE a setter may employ a shift indicator such as:
state sending son back ...
... here, the abbreviation for son (S) is being 'sent back' in the word STATE. So STATE, having the S sent back two places in the word, becomes TASTE.
To make STATE from TASTE the setter employs a letter shift that sends S forward rather than back (in this case by a positional indicator)
taste the middle first ...
... here a central selector THE MIDDLE is used to indicate S and is followed by a positional indicator FIRST. The result is that the middle of TASTE (S) goes first, making TASTE become STATE.
Any words that fairly indicate letter movement or change of position may be used as letter shift indicators. Here are some more examples:
letter shift indicators - PROMOTING/DEMOTING
Finally, as with many indicators, the indicator will be dependent on whether the clue sits in a down or across position. For a down clue RISING or FALLING would work well to indicate a letters movement, but they would not work in an across clue.
Here is an example from a down clue:
Tawdry country bar sees soprano on the slide (9)
tawdry - definition
country - state
bar - less
sees soprano on the slide - S letter shift indicator (S is an abbreviation for soprano)
(->)TA(->S)TELESS = TASTELESS
NOTE: There is more than one S here, but, as it's a down clue, only one S can go on the slide as the other two are already at the bottom of the word.
Also note that two bits of fodder COUNTRY & BAR are taken as one piece of fodder in this instance - if they weren't, then the letter shift indicator would have to be next to COUNTRY and not BAR. Taking fodder as separate objects or as one is up to the setter and it can affect the verb form of the indicators used.
Sometimes two letters can be shifted by indicating they change places - here is an example:
Stomach-turning cheese, yours truly produces floater (6)
stomach-turning - central letter swap indicator
cheese - brie
yours truly - me
produces - link (definition made from wordplay)
floater - definition (a boat is something that floats)