This study investigates the effects of stoichiometry on the propagation of triple flames in counterflowing fuel and oxidizer streams. Most previous research has focused on symmetric cases where the stoichiometric mixture fraction is 1/2, resulting in equal strengths of lean and rich premixed flames with a trailing diffusion flame. However, in realistic scenarios, the stoichiometric mixture fraction often deviates significantly from unity, leading to one premixed wing dominating over the other. The authors use a simplified model, primarily through numerical integration, to explore the impact of stoichiometry. They find that when the stoichiometric mixture fraction deviates from 1/2, one of the premixed wings becomes dominant, while the diffusion flame and the other premixed flame become very weak. These curved, partially premixed flames are relevant in practical configurations. A kinematic balance is also presented to predict the shape of the front and propagation velocity under low stretch and low curvature conditions. The study considers equi-diffusional systems with unity Lewis numbers to clarify the effects of stoichiometry without introducing additional complexities like variable densities or heterogeneous mixtures. The analysis involves a one-step irreversible reaction for chemistry, with the governing equation solved for the temperature field and reactant concentrations through a mixture fraction. Numerical results show that the extinction strain rate for the one-dimensional trailing diffusion flame is proportional to the stoichiometric planar velocity squared divided by the thermal diffusivity. The influence of stoichiometry on the flame structure is evident, with the symmetric triple-flame structure breaking down for higher stoichiometric ratios, leading to a C-shaped flame with one wing evolving into the trailing diffusion flame. The study concludes that not all partially premixed flames in counterflow configurations exhibit the classical tribrachial structure. At high dilution-adjusted stoichiometric fuel-air ratios, such as those in methane-air flames, the diffusion flame may fade into the lean wing, and the triple flame may evolve into a fuel-rich C-shaped premixed flame. However, heat release can modify this configuration, bringing the trailing diffusion flame back into visibility. Symmetric triple flames are not expected to be common in practical situations.This study investigates the effects of stoichiometry on the propagation of triple flames in counterflowing fuel and oxidizer streams. Most previous research has focused on symmetric cases where the stoichiometric mixture fraction is 1/2, resulting in equal strengths of lean and rich premixed flames with a trailing diffusion flame. However, in realistic scenarios, the stoichiometric mixture fraction often deviates significantly from unity, leading to one premixed wing dominating over the other. The authors use a simplified model, primarily through numerical integration, to explore the impact of stoichiometry. They find that when the stoichiometric mixture fraction deviates from 1/2, one of the premixed wings becomes dominant, while the diffusion flame and the other premixed flame become very weak. These curved, partially premixed flames are relevant in practical configurations. A kinematic balance is also presented to predict the shape of the front and propagation velocity under low stretch and low curvature conditions. The study considers equi-diffusional systems with unity Lewis numbers to clarify the effects of stoichiometry without introducing additional complexities like variable densities or heterogeneous mixtures. The analysis involves a one-step irreversible reaction for chemistry, with the governing equation solved for the temperature field and reactant concentrations through a mixture fraction. Numerical results show that the extinction strain rate for the one-dimensional trailing diffusion flame is proportional to the stoichiometric planar velocity squared divided by the thermal diffusivity. The influence of stoichiometry on the flame structure is evident, with the symmetric triple-flame structure breaking down for higher stoichiometric ratios, leading to a C-shaped flame with one wing evolving into the trailing diffusion flame. The study concludes that not all partially premixed flames in counterflow configurations exhibit the classical tribrachial structure. At high dilution-adjusted stoichiometric fuel-air ratios, such as those in methane-air flames, the diffusion flame may fade into the lean wing, and the triple flame may evolve into a fuel-rich C-shaped premixed flame. However, heat release can modify this configuration, bringing the trailing diffusion flame back into visibility. Symmetric triple flames are not expected to be common in practical situations.