Reborn as the Disgraced Crown Prince, I Use History Books to Crush the Zhenguan Era!

Li Jiancheng, a history student who'd given up on life, transmigrates as the Li Jiancheng doomed to die at the Xuanwu Gate Incident. He awakens the "Life-for-Sale Heavenly Tome": win once, and lose three years of your lifespan; lose once, and you die on the spot! Want to stay alive? First recruit twenty-eight generals as "human shields," then stake the Great Tang itself on a gamble for an age of unprecedented prosperity!

System alert: Kill Li Shimin and live. Cost: 3 years of your lifespan! Li Jiancheng nearly spits blood. "I only had two years left to begin with!" To extend his life, he frantically recruits generals, brings in civil officials, and seizes territory, turning the Great Tang into a "lifespan exchange." Slay Jieli Khan at the Wei River: minus three years. Destroy the Turks on a snowy night: minus five years. Smelt steel in a blast furnace: minus one year... The twenty-eight generals kneel together and plead, "Your Majesty, stop checking! We'll gladly give our lives and pay the cost for you!" When his hair has turned white as snow and envoys from every nation come to pay tribute, Li Jiancheng slams his hand on the table. "I traded thirty years of my life for three hundred years of prosperity for the Great Tang. Worth it!"

When the final star lights up, the historian puts pen to paper:

"Taizu Jiancheng rose like a dragon at Xuanwu. With twenty-eight veteran generals, he brought the realm under his might and opened an age of a thousand years of order."