Two were built, the maiden flight of the first was in May 1939 and received the registration J-AARD which is the subject of the Amodel kit. There is no information regarding the second KS-1.
Below is a photo from a vintage publication of rather poor quality (our apologies) that shows the markings apart from the J- registration that seem to be missing from the box art of the kit.
Tachikawa KS-1 Data:
Wing: wooden, fabric covered / Fuselage: welded steel tube, fabric covered.
Engine: Jinpu Model 3 150hp air-cooled radial 7 cylinders / Propeller: Wooden, two blades Model Otsu fixed pitch, diameter 2.2m / Span: 9.996m / Weight, empty: 722kg, full: 1,140kg, cargo: 358kg / Power loading: 7.6kg/hp / Fuel: 2 tanks 140+69lit / Fuel type: 62 Octane
Max speed: 185km/h @ 1,000m / Cruising speed: 135km/h @ 1,000m / Landing speed: 80km/h / Climb to 3,000m in 33.35min / Take-off distance: about 250m / Crew: 4
More about the markings, possible colours and information about the other Ministry of Railways aircraft, tomorrow.