
When it comes to froth, it gives you a pretty good indication of the quality of the beer you're drinking, so when trying something new I pour it straight down - smack into the bottom of the glass - so as to generate as much foam as possible.
With the Jap beers you're going to be impressed, but try this with any of the main global "brands" and you'll likely get stomach convulsions when trying the foam, and that doesn't speak well of the beer itself... But then those so-called global brands are like "brewed today, bottled tomorrow." Or later today even...

I like weiss beers too, but have have had way too many in recent years.