Batter is key.

Kagu Ra Zaka. 03 9827 2608.
266 Toorak Road, South Yarra. Melbourne.
Engrish: 7 BON: 7 (can't actually tell the age)
TTDWW: Read 16 pages of a chick novel.

Kagu is situated opposite the Como building along Toorak Rd, 10 minutes away from Ramen's work place.
Tonkatsu is a bowl of rice topped with deep fried pork cutlet, egg and condiments. Sometimes you get onions, sometimes spring onions etc.
Restaurants rarely, in this case Kagu Ra Zaka, offers the choice of your Katsudon's cutlet to be pork or chicken.
Ramen chose the latter.
Have you ever had that experience eating a cutlet, when the batter just separates from the meat, or grease just go spurting out of your mouth? Fortunately, Kagu's Katsudon did neither of that.
The soy sauce normally comes next in terms of the hierarchy of taste. Which is fairly basic, because you seldom screw up soy sauce.
In fact, this is probably the best Katsudon Ramen has eaten for a while. For $8, he is sure to return. The Chinese owned Japanese stall in Como charges $8.50, and they don't even have a fraction of Kagu's dining atmosphere.
Interesting fact: Students in Japan eat Katsudon before exams because 'Katsu' also means 'to be victorious' in Japanese.