What are five important artifacts that Japan in the Middle Ages have contributed to the world?

Question

These 'artifacts' do not have to be a concrete object. It could be something intangible like a law or a belief.

Answer 1

I'll give you three:

the short Japanese poetry of 17 syllables (haiku)

Japanese lacquer ware (urushi)

Japanese Buddhism (Bukkyou)

Answer 2

(More than five, but you can pick and choose).

Spread of Bhuddism to all classes of Japanese.

Japanese style of feudalism complete with castles and "knights" in the form of samurai warriors.

Belief in kamikaze/"divine winds" created by Shinto gods which protect Japan from foreign invasion after dual destruction of the Mongol army's armadas in both 1274 and 1281 by powerful typhoons.

Japanese architecture (pagoda roofs, sliding paper/wood screens, etc.) with beautiful gardens/landscaping.

Zen tea rituals.

Endless war brings militarism to the forefront in Japan, pervading almost every aspect of society. The government is actually controlled by a supreme warrior called a Shogon, while the Emperor is left with no power whatsoever.

Bhuddist influenced literature such as Essays in Idleness and Noh (musical drama) theatre.