As many razor owners know Schick Injector razors tend be classified using this system here. http://safetyrazors.net/schick/schicktech.htm As far as the I and J razors the classifications are not complete and some of the dates are inaccurate. First as we can see here with copyright in the ad itself that the I2 hydro magic was first introduced in 1954 not 1955. Second is that the I and J models were sold together and not I models first then J models as seen here in this ad for Fathers Day 1955. So we can say for sure J models were introduced at least as early as 1955 not 1958. So how to sort all the models out. First distinction is between razors with hydro magic levers and razors without. The next distinction will be based upon how the branding is stamped. For Hydro magic you have 3 types ones stamped Eversharp Schick, Eversharp Hydro Magic and Schick Golden 500. For non hydro magic lever razors you have Eversharp Schick, Schick Safety Razors and Schick. How do we determine which order the stampings follow well for starters for hydro magic razors it is straightforward, the earliest version would have been prior to marketing coming up with hydro magic name for the lever so the order would be. Eversharp Schick -> Eversharp hydro magic -> Schick Golden 500. It is highly unlikely they would have unbranded the hydro magic afterwards and we know the other which order they came in 2 by how the levers were made. For the non hydro magic lever razors aka the I1 variants, J1 variants and J2 we can first make an assumption they started out with larger blade gap exposure to a smaller blade gap exposure as seen here. The only J1 and I1 variants not pictured are the ones stamped Schick Safety Razors, they had larger blade exposure like the other white handle I1 and J1 razors. So finally which order were they produced. Based upon how razors were made in this time period they went from more to less gap exposure and from more aggressive to mild. Having used almost all the variants I can say through testing following this progression they would have been produced in the following order. Eversharp Schick -> Schick Safety Razor -> Schick Next 2 posts will cover hydro magic razors and non hydro magic razors and their variant grouping. Final post will contain category grouping based upon tested razors. How I group the razors to keep within Appleby's original designations is the following. First by handle either they have an I style handle or J style handle. Then to keep within the original I1,2 and J1,2,3,4 the variants are distinguished by the following using a v1,2,3,4,etc. appended to the original Appleby designations. For I and J models the first variant distinction is by the branding stamp on the razor head. The second distinction applies only to hydro magic razors and the variants which is determined by the style of lever. The final distinction is a category ranking which tells us which razors shave the same regardless of other distinctions.