Well, 170 years ago is 1844, towards the end of the Edo period. Japan had been unified, and was enjoying two centuries of peace. There weren't really any major Japanese conflicts leading up to that time.

The nearest conflict is Oshio Heihachiro no Ran, which took place in 1837. This rebellion was put down in less than a day, and the rebels, numbering around 300, consisted primarily of peasant farmers. The only mention of weapons I can remember off the top of my head was the acquiring of a cannon by Oshio in preparation for the rebellion.

The next major conflict would be the Boshin War, in 1868. By this point guns certainly had supplemented bows and arrows. Both the Shogunate and Imperial forces fought primarily with firearms.

I believe the last account of a bow and arrow being used is in 1877, during the Satsuma Rebellion. In the book 鹿児島つれづれ草, 勝目清 writes that his archery master, who fought for Satsuma, told him that 桂久武 once used a bow to kill an enemy commander. However, even if this was true, the overwhelming majority of soldiers relied upon guns, not bows and arrows.