Invention of Gunpowder

Lore & Background

In a world reset to stone, chemistry becomes the ultimate weapon. Senku understands that fighting Tsukasa’s army with fists is futile; they need leverage. The formula for black powder relies on three specific ingredients: sulfur for fuel, charcoal as carbon, and saltpeter (potassium nitrate) as the oxidizer. While charcoal was abundant, sourcing high-quality saltpeter required a dedicated fermentation farm using human waste and significant time to produce, making it the primary bottleneck. In contrast, sulfur was located relatively quickly at a volcanic deposit once identified. Senku developed the gunpowder after escaping Tsukasa's imprisonment, collaborating closely with Chrome—who was actively involved in the entire process, including the construction of the saltpeter farm—not just later firearm production.

In Their Own Story

The air in the makeshift laboratory smelled of sulfur and damp earth. Senku adjusted his goggles, watching the mixture in the mortar with intense focus. A single spark could mean disaster if the ratio was off. He dipped a finger into the fine black dust, tasting the faint metallic tang of success. Beside him, Chrome held his breath, knowing this powder held the weight of their survival. With a nod, Senku struck the flint. The flash blinded them for a split second before a controlled roar erupted from the test barrel, sending smoke curling into the stone sky.

Reader's Guide

The Kingdom of Science faces an existential threat as Tsukasa Shishio’s Empire marches toward their base. Realizing physical strength cannot match force, Senku Ishigami prioritizes chemistry over combat. He identifies gunpowder as the equalizer needed to defend their territory and protect the ongoing research into a cure for petrification. The primary obstacle is sourcing sulfur, a rare mineral in this post-apocalyptic world. Kingdom members lead an expedition to locate volcanic deposits where sulfur might be found safely. While the team gathers the necessary charcoal and saltpeter from compost, Senku perfects the mixing ratio required for stable combustion without premature detonation. Once synthesized, the black powder is packed into a cannon constructed from stone and metal scraps. The weapon fires successfully during the Empire’s assault, halting their advance with explosive force. This invention marks a turning point where science temporarily gains the upper hand against brute might, proving knowledge can reshape warfare in the Stone World.

Did You Know?

• Saltpeter was synthesized from human waste and compost due to the lack of modern mining.
• Sulfur was located relatively quickly at a volcanic deposit, whereas saltpeter required a dedicated fermentation farm.
• The initial application focused on a cannon rather than small firearms for maximum impact.
• Senku developed gunpowder after escaping Tsukasa's imprisonment, working alongside Chrome—who helped build the saltpeter farm and was integral to the entire development process.