I understand your reason, WHY you wanted to attack Szechwan. It doesn’t mean it was a good decision.
When Russia puts so much effort into Japan, just react accordingly with Germany. Russia is doomed after that investment into China. Making a super risky move with Japan just to speed up the process is totally unnecessary.
You had bad dice in that one fight, but you didn’t lose because of bad dice.
To make it more simple: You had around 80% chance success in that attack. If it fails, you give up (as you did). That means that 1 in 5 times, you would lose the game. And for what? For defeating Russia one round earlier in 4 out of 5 times?