Ignoring KPM's trivial diversion...
The problem you have, as well as KPM and others, is that you use imperfect English translations to fit the terminology of VT to whatever you need it to say.
In English, we say "simultaneous attack and defense" or "simultaneous defense and counter" because we prefer a terse expression to match the maxim in Chinese. But English is not as expressive or exact in so few words as Chinese. Lin siu daai da is in fact not saying "simultaneous" and not saying "defense" in general to allow for dodging to be a possible meaning.
I shall explain.
"Lin... daai..." is a common Chinese grammatical structure, and no part of it means "precisely simultaneous" or even just "simultaneous".
It means "both... and...", "... as well as...", "... together with...".
Literally, lin means to link; continuous; in succession, and daai means to lead; to bring along.
So what you get when you insert siu (eliminate; dispel; remove) and da (to hit; to strike) is an idea of deflection closely followed by a strike in one continuous action.
Not two arms acting at precisely the same time, not one arm with two separate actions/beats (block then punch), and definitely not just dodging which doesn't displace (siu) the limb.
It's one continuous action with two functions happening in such quick succession that we just call it simultaneous in English.
"Da-sau jik si siu-sau" spells it out for you. The same arm accomplishes both of the above. That's the unique skill of VT.
Using two arms in response to a single punch is not special. It actually violates simplicity, directness, and efficiency principles when it's possible to use just one arm for the task.
Even when using a simultaneous helping action (e.g. paak-da; jat-da), LSDD is still referring to the striking arm having this dual-functioning capability should further obstruction be on its path.
For example, I use paak with a simultaneous punch. That punch displaces the opponent's rear arm as it strikes. LSDD is still referring to that striking arm which is also displacing, not both arms. The paak is just auxiliary, done when my original punch has been interrupted or I'm out of position to use just one arm. Then I may return to my primary punching idea, rotating two arms that both have LSDD capabilities.
In our Yip Man VT we teach that simultaneous defense and counter (lin siu dai dar) uses two hands moving at precisely the same time to defend and attack, as with tan-da, gaun-da, pak-da, etc.
For us, da sau jik si siu sau is usually associated with using one hand to defend and counter, as when your punch deflects your opponenent's punch and proceeds to hit. The deflection comes an instant before the strike hits it's target, so although extremely efficient, this is not precisely simultaneous.
The problem you have, as well as KPM and others, is that you use imperfect English translations to fit the terminology of VT to whatever you need it to say.
In English, we say "simultaneous attack and defense" or "simultaneous defense and counter" because we prefer a terse expression to match the maxim in Chinese. But English is not as expressive or exact in so few words as Chinese. Lin siu daai da is in fact not saying "simultaneous" and not saying "defense" in general to allow for dodging to be a possible meaning.
I shall explain.
"Lin... daai..." is a common Chinese grammatical structure, and no part of it means "precisely simultaneous" or even just "simultaneous".
It means "both... and...", "... as well as...", "... together with...".
Literally, lin means to link; continuous; in succession, and daai means to lead; to bring along.
So what you get when you insert siu (eliminate; dispel; remove) and da (to hit; to strike) is an idea of deflection closely followed by a strike in one continuous action.
Not two arms acting at precisely the same time, not one arm with two separate actions/beats (block then punch), and definitely not just dodging which doesn't displace (siu) the limb.
It's one continuous action with two functions happening in such quick succession that we just call it simultaneous in English.
"Da-sau jik si siu-sau" spells it out for you. The same arm accomplishes both of the above. That's the unique skill of VT.
Using two arms in response to a single punch is not special. It actually violates simplicity, directness, and efficiency principles when it's possible to use just one arm for the task.
Even when using a simultaneous helping action (e.g. paak-da; jat-da), LSDD is still referring to the striking arm having this dual-functioning capability should further obstruction be on its path.
For example, I use paak with a simultaneous punch. That punch displaces the opponent's rear arm as it strikes. LSDD is still referring to that striking arm which is also displacing, not both arms. The paak is just auxiliary, done when my original punch has been interrupted or I'm out of position to use just one arm. Then I may return to my primary punching idea, rotating two arms that both have LSDD capabilities.