Won first prize in shogi tournament (nyanko)

I won first prize in shogi tournament of Omiya shogi centre the other day.
http://www7b.biglobe.ne.jp/~oomiyasc/

In many games, I had a bad position.
But it is necessary to play perseveringly and get results in that bad situation in order to achieve good results. I think this is common in daily life.

figure. 1 tournament table of best 16 (actually, 32 players attended)

Figure. 2 is one position of this day's game.
I was on defencive until this position and the opponent moved R-6e+, fork on Rook and Bishop.
What do you move in the position?

figure. 2

In this position, my own castle is still solid, so it's chance to go on the offencive, without escaping Rook or Bishop.
Therefore, B*3a is technique.
And the game proceeded Gx3a, Bx3a+, Kx3a, R-5a+, S*4a, G*4b (figure. 3).
The opponent's castle becomed thin and I fulfilled the attack after this.

figure. 3