Twelve low-dust chalks from Rikagaku, the Japanese company behind Kitpas. They are made from calcium carbonate and finely ground scallop shells and give flat, bright colours on a chalkboard or paving stones. Dissolved in water, they create a watercolour-like effect. They are used in Japanese schools.

• 12 colours: white, pink, red, orange, yellow, light green, dark green, blue, purple, lilac, brown, grey
• Non-toxic, allergen-free
• From 4 years