Centuries ago in this part of the world, the Nusantara, there lived a wise sultan. He ruled over a remarkably fertile country. Lush rice fields watered by clear running rivers stretched out for miles around an active volcano, Gunung Berapi. Year after year, the harvests were bountiful. His people became numerous.

The sultan was mightily pleased because his revenue came from a head tax paid in rice. Their bellies full, his subjects were happy to pay this tax. But in recent years, the sultan’s tax revenue began to show a steady decline. The granaries, once full, were often depleted before the next harvest. The sultan was puzzled.

It was surely time for him to tour the villages and districts of his realm. Everywhere he went, his subjects looked well-fed, well-clothed, and full of cheer.

The women, looking their best, were dressed in rich fabrics and jewellery. District chiefs wore pearl necklaces and wavy daggers set with precious stones tucked into their waistbands.

Children, full of vigour and energy, spun tops, flew kites, and played ball games. The sultan said to himself, looking annoyed: “My lands are fertile but my khazanah (treasury) is near empty! I suspect no one is paying their taxes in full.”

As they say, “Happy sultans are all happy in the same way but each angry sultan is angry in his own way.”

He was determined to get to the bottom of things. If nothing...