Out of all the battleships produced prior to, during and right after WW2 which was the superior fighting ship. I believe the last (best) battleships produced by each nation were:
France
Richelieu Class
47,584 tonnes full load
247.9 meters
30 knots
8 x 15 inch guns
Germany
Bismark Class
50,900 tonnes full load
251 meters
30.8 knots
8 x 15 inch guns
Great Britian
Vangard Class
48,500 tonnes
246.8 meters
30 knots
8 x 15 inch guns
Italy
Littorio class
45,963 tons full load
237.8 meters
31.5 knots
9 x 15 inch guns
Japan
Yamato class
72,820 tonnes
263 meters
27 knots
9 x 18.1 inch
United States
Iowa class
58,000 tons full load
271.27 meters
33 knots
9 x 16 inch
France
Richelieu Class
47,584 tonnes full load
247.9 meters
30 knots
8 x 15 inch guns
Germany
Bismark Class
50,900 tonnes full load
251 meters
30.8 knots
8 x 15 inch guns
Great Britian
Vangard Class
48,500 tonnes
246.8 meters
30 knots
8 x 15 inch guns
Italy
Littorio class
45,963 tons full load
237.8 meters
31.5 knots
9 x 15 inch guns
Japan
Yamato class
72,820 tonnes
263 meters
27 knots
9 x 18.1 inch
United States
Iowa class
58,000 tons full load
271.27 meters
33 knots
9 x 16 inch