Exact timing on force play
 

B1 hits ground ball to F4 who then throws to F3. While standing on the bag, F3 deflects the ball into the air with his mitt before securely catching it in his mitt. B1 reaches the bag a "split second" after the ball is deflected, but before it is caught securely. Is he safe?

Read the definition of tag. The answer is there.

Safe.

Just curious as to why you asked. I'm not sure why there would be any question if the BR reaches base prior to F3 catching the ball.
Not being critical, just wondering your thought process.

1. I was comparing the play to the one where a runner may leave his base after a fly ball is touched by a fielder, even if it is subsequently caught by another fielder.

2. I had read or heard that umpires listen for the ball hitting the glove when calling the close force play. Is that true?

Two different rules, two different concepts.

Yes, but we still see the ball.

If the runner couldn't leave on the touch, the fielder could "juggle" the ball all the way to the infield, thus preventing the advance. An infielder on a force play, can't get that same advantage.

And, the out at first isn't a force play. ;)

2nd, 3rd, and home are eligible for force plays. The BR is simply put out before reaching first base. The BR does the forcing. He is not forced. Think about the rule for scoring runs on plays where the third out is recorded. It talks about force plays and/or the BR being out before reaching first.