This study investigates the influence of stoichiometry on the structure and propagation of triple flames in counterflow configurations. Traditionally, research has focused on symmetric cases where the stoichiometric mixture fraction is 1/2, but in reality, stoichiometric ratios often deviate significantly from this value. The study uses a simplified model to analyze how stoichiometry affects flame behavior, particularly in systems with equi-diffusional properties. When the stoichiometric mixture fraction deviates from 1/2, one of the premixed flames dominates, leading to a weak diffusion flame and the other premixed flame. These partially premixed flames are relevant in practical combustion scenarios. The study also explores the kinematic balance of thin flames, showing that a simple balance can predict flame front shape and propagation velocity in low-stretch and low-curvature conditions. Numerical results demonstrate that the extinction strain rate depends on the stoichiometric ratio, with higher ratios leading to different flame structures. For S = 17.2, the flame takes a C-shape, with the trailing diffusion flame becoming less significant. The flame velocity is found to depend on strain rate, with the flame propagating faster at higher strain rates. The analysis also shows that the thin-flame approximation can be used to predict flame behavior, even with complex chemistry. However, the predictions for propagation velocity are less robust than those for flame shape. The study concludes that not all partially premixed flames in counterflow configurations exhibit the classical tribrachial structure. Instead, under certain conditions, the flame can evolve into a fuel-rich C-shaped flame. The study also highlights the utility of thin-flame approximations in simplifying complex combustion problems, particularly in the limit of small strain rates.This study investigates the influence of stoichiometry on the structure and propagation of triple flames in counterflow configurations. Traditionally, research has focused on symmetric cases where the stoichiometric mixture fraction is 1/2, but in reality, stoichiometric ratios often deviate significantly from this value. The study uses a simplified model to analyze how stoichiometry affects flame behavior, particularly in systems with equi-diffusional properties. When the stoichiometric mixture fraction deviates from 1/2, one of the premixed flames dominates, leading to a weak diffusion flame and the other premixed flame. These partially premixed flames are relevant in practical combustion scenarios. The study also explores the kinematic balance of thin flames, showing that a simple balance can predict flame front shape and propagation velocity in low-stretch and low-curvature conditions. Numerical results demonstrate that the extinction strain rate depends on the stoichiometric ratio, with higher ratios leading to different flame structures. For S = 17.2, the flame takes a C-shape, with the trailing diffusion flame becoming less significant. The flame velocity is found to depend on strain rate, with the flame propagating faster at higher strain rates. The analysis also shows that the thin-flame approximation can be used to predict flame behavior, even with complex chemistry. However, the predictions for propagation velocity are less robust than those for flame shape. The study concludes that not all partially premixed flames in counterflow configurations exhibit the classical tribrachial structure. Instead, under certain conditions, the flame can evolve into a fuel-rich C-shaped flame. The study also highlights the utility of thin-flame approximations in simplifying complex combustion problems, particularly in the limit of small strain rates.