Metro Manila (CNN Philippines) — President Rodrigo Duterte is again meeting with a "special friend who's closer than a brother."

This was how he described Japan after his official visit there last October.

Now it's Japanese Prime Minister Shinzo Abe's turn to visit the Philippines.

Although the topic of federalism has been discussed since the 1971 Constitutional Convention, there are still many areas that are not clear even to political analysts. In the interest of full disclosure, I will state now that I have always been in favor of a federal system of government and I have written several columns in the past about this topic. However, today I want to focus on clarifying certain issues.

DAVAO CITY, Philippines -- (UPDATE - 12:53 p.m.) Davao City Mayor Rodrigo Duterte announced plans on Tuesday for a radical overhaul of the country's unitary system of government that would empower the provinces.

At the same time, the incendiary politician reiterated his vow of a relentless crackdown on crime after claiming a landslide presidential victory built on foul-mouthed populist tirades that exposed deep voter anger at the establishment.