Cutting Squares in to the edge of wood?

[hachiman]

Hi

Absolutely newbie at DIY so forgive me for my naivety!

I have a small piece of wood that is perhaps the half the size of a beer coaster and perhaps half an inch thick. I need to cut a square shape out of it for a gate latch to fit in. In the diagram the white piece is the part I want out. How do I cut this out and with what tools?



Thanx from a newbie.

 

[footprints]

saw down each side and cut the waste out with a sharp chisel

 

[foxhole]

Or a coping saw.