Ed Gaillard wrote:

That's an 'hourglass' time limit, in effect.

Yes. That was also senior master DB's instant reaction
to my proposal, long years ago.

It's not a bad idea. The only problem is that games could be very
long. Imagine if each side averaged 30 minutes per move, for example.
But at least it would require both sides wanting to spend a lot of
time for that to happen.

-ed g.

The emphasis should be on BOTH. The point is that it should be,
within a reason, up to the world champion and his/her challenger
how fast they want to move in their match, depending on the
position on the board.

Regards,

Wlod