Where is he..?

In fact, this is not the first time that Orzon has witnessed something like this, as all the elders of the Nihari Union Sect and chiefs of the giants' tribes had seen Jabba take out his war hammer earlier in the last meeting, but no one understood what happened... 

It crossed no one's mind that there is a way to hide things in a pocket space, it was just too far fetched an idea

Perhaps it is a special technique that Robin devised to hide that hammer specifically for Jabba and make it appear at his will. like using the Darkness Heavenly Major Law or something...

Everyone's fascination quickly faded upon thinking about this, realizing that Robin wouldn't do such a thing for them. 

The concealment of a personal weapon... A great but unnecessary craft, it is nice to have but is not something that they must have at least, can't his hammer just be placed on his back as his father and ancestors did?