when did hashirama got rods on his back

[jiraya namikaze]

When........................?

 

[Clouds]

During the last fight?

Before he was revived. >_>

 

[Matt]

Your late if you only just noticed he was using them to try and hold down hashi to get his sage powers

 

[Itachi Edo]

Read the last chapter where Madara turned on Obito. The rods are in the 1st Hokage's back during their fight. Hell, even before that rods were in Hashirama's back.