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In an effort to improve our understanding of the spiral arm structure of theMilky Way, we use Classical Cepheids (CCs) to increase the number of youngtracers on the far side of the Galactic disk with accurately determineddistances. We use a sample of 30 CCs, discovered using near-infrared photometryfrom the VISTA Variables in the V\'ia L\'actea survey (VVV) and classifiedbased on their radial velocities and metallicities. We combine them withanother 20 CCs from the literature for which VVV photometry is available. Thecompiled sample of CCs with homogeneously computed distances based on VVVinfrared photometry was employed as a proof of concept to trace the spiralstructure in the poorly explored far side of the disk. Although the use of CCshas some caveats, these variables are currently the only available youngtracers in the far side disk for which a numerous sample with accuratedistances can be obtained. Therefore, a larger sample could allow us to make asignificant step forward in our understanding of the Milky Way disk as a whole.We present preliminary evidence that CCs favor: a spiral arm model with twomain arms (Perseus and Scutum-Centaurus) branching out into four arms atgalactocentric distances, $R_\mathrm {GC}\gtrsim5-6\,\mathrm{kpc}$; theextension of the Scutum-Centaurus arm behind the Galactic center; a possibleconnection between the Perseus arm and the Norma tangency direction. Thecurrent sample of CCs in the far side of the Galaxy are in the mid-plane,arguing against the presence of a severely warped disk at small Galactocentricdistances ($R_\mathrm {GC}\lesssim12\,\mathrm{kpc}$) in the studied area. Thediscovery and characterization of CCs at near-IR wavelengths appears to be apromising tool to complement studies based on other spiral arm tracers andextend them to the far side of our Galaxy.

Using classical Cepheids to study the far side of the Milky Way disk. II. The spiral structure in the first and fourth Galactic quadrants