Iran's threat to completely close the Strait of Hormuz caused Japan's Nikkei to open down 4% for the day.

Japan imports a large portion of its energy from the Middle East.
Every ship passing through the Strait of Hormuz is vital to Japan.
Iran's threat to close this strait is pushing up expectations for oil prices and creating a panic sell-off in the Nikkei because it will explode Japanese companies' costs.
So for us to take a breath of relief across all markets, this Strait of Hormuz situation shouldn't drag on much longer.
Because markets don't like uncertainty.
If this crisis becomes permanent, not just Japan, but the entire global supply chain will break down.
Since investors are currently in risk-off mode, they're pulling money to safe havens.