The proven Zacks Rank system focuses on earnings estimates and estimate revisions to find winning stocks. Nevertheless, we know that our readers all have their own perspectives, so we are always looking at the latest trends in value, growth, and momentum to find strong picks.

Looking at the history of these trends, perhaps none is more beloved than value investing. This strategy simply looks to identify companies that are being undervalued by the broader market. Value investors use a variety of methods, including tried-and-true valuation metrics, to find these stocks.

Luckily, Zacks has developed its own Style Scores system in an effort to find stocks with specific traits. Value investors will be interested in the system's "Value" category. Stocks with both "A" grades in the Value category and high Zacks Ranks are among the strongest value stocks on the market right now.

One stock to keep an eye on is J. Sainsbury (JSAIY). JSAIY is currently sporting a Zacks Rank of #1 (Strong Buy), as well as a Value grade of A. The stock is trading with a P/E ratio of 13.45, which compares to its industry's average of 28.33. Over the last 12 months, JSAIY's Forward P/E has been as high as 15.95 and as low as 11.05, with a median of 12.73.

We also note that JSAIY holds a PEG ratio of 2.57. This figure is similar to the commonly-used P/E ratio, with the PEG ratio also factoring in a company's expected earnings growth rate. JSAIY's PEG compares to its industry's average PEG of 3.25. Over the past 52 weeks, JSAIY's PEG has been as high as 3.60 and as low as 0.38, with a median of 2.60.

If you're looking for another solid Retail - Supermarkets value stock, take a look at Marks and Spencer Group (MAKSY). MAKSY is a # 2 (Buy) stock with a Value score of A.

Marks and Spencer Group is currently trading with a Forward P/E ratio of 14.48 while its PEG ratio sits at 0.67. Both of the company's metrics compare favorably to its industry's average P/E of 28.33 and average PEG ratio of 3.25.

MAKSY's price-to-earnings ratio has been as high as 15.50 and as low as 9.19, with a median of 11.68, while its PEG ratio has been as high as 1.66 and as low as 0.53, with a median of 0.73, all within the past year.

Additionally, Marks and Spencer Group has a P/B ratio of 2.97 while its industry's price-to-book ratio sits at 7.15. For MAKSY, this valuation metric has been as high as 2.97, as low as 1.43, with a median of 1.85 over the past year.

These figures are just a handful of the metrics value investors tend to look at, but they help show that J. Sainsbury and Marks and Spencer Group are likely being undervalued right now. Considering this, as well as the strength of its earnings outlook, JSAIY and MAKSY feels like a great value stock at the moment.