Woodworking question with diagram: Which tool does the job?

Here is a link to the picture of what I want to achieve:

http://picasaweb.google.com/lh/photo/0NA2OYZ1Y2rSSH2bXGop5VAg6A1hoEn-wSLXN7KfURo?feat=directlink

What tool can achieve this notch in the wood? The dimensions of the block are 2×6x4, and the notch goes about 1.5 in in. I can settle for 1 in in.

If you’re wondering what this is, it’s a knife block. I am going to put magnets I salvaged from old hard drives in that notch.

So what woodworking tool/method can achieve this?

Thank you!

Just an added note, to shoo away the negative-nancies – I don’t need advice on this question – I need solutions. Thanks again!