Select interposing piece (nyanko)

It is said that one of the greatest characteristic of shogi is you can drop the piece which you took.
It is necessary to select interposing piece accurately for increasing win ratio.

What do you respond the Check R*5h in figure. 1?

figure. 1

If you move S*4h or B:4h, then G*2h, K-4i (if Kx2h, you are mated by Rx4h+, G*3h, S*3i), Rx6h+ (figure. 2).

In figure. 2, my King are Brinkmake (you can't prevent both mate G*5h and G*3h simultaneously).

figure. 2

So R*4h is accurate interposing piece in figure. 1 (figure. 3).

By interpose Rook (R4h instead of S4h in figure. 2), you become to be able to take Rx4h if the game will proceed just like figure. 2.

figure. 3

From figure. 3 the real game proceeded as Gx2h, K-4i, Rx4h+, Kx4h, R*3h, K-5g, G*6f, Kx6f, +R-6h, P*6g (figure. 4).
I succeeded to stop the opponent's attack. After that I counterattacked and won.

figure. 4

The entire Kifu is following. In fact, I failed piece-building in opening, then the opponent attacked and I maneged to defended.