Another of Seki's contributions was the rectification of the circle, i.e., the calculation of pi; he obtained a value for π that was correct to the 10th decimal place, using what is now called "Aitken's delta-squared process," rediscovered in the 20th century by Alexander Aitken.
Outra das contribucións de Seki foi a súa rectificación do círculo, isto é, o cálculo de pi; obtivo un valor para π que foi correcto até o décimo valor decimal, usando un método redescuberto no século XX por Alexander Aitken.