Never knowingly undersold. It's worked for John Lewis for years. And now Asda underselling in another sense of the word, according to the latest stats is hoping its new Price Guarantee website will "end the phoney war" of prices and promotions.

So will it work? Rivals have been quick to dismiss it as a web-based gimmick. And interestingly, with 40-odd days still to go till the World Cup, it's involved in "a kamikaze beer war" with Tesco (see p6).

But it will be fascinating to see what impact this innovative effort at transparency will have on the market, because I do think judging by the letters to customer enquiries we are copied in on that for every consumer who gets excited about the latest "amazing bargains", just as many people feel confused by the claims and counterclaims, while a significant minority feel just plain duped by the wild swings in prices from week to week.

The other question for me is how much this will cost Asda. Research by Valassis last June found 17% of households had printed a grocery coupon or voucher found online in the past year, with 48% of those regularly using them when they go grocery shopping.

Applied to Asda's 18m weekly shoppers, this suggests 1.5m could redeem the vouchers, which could add up to one hell of a hit for Asda but for the fact that, as The Grocer 33 shows week in, week out, it's always there or thereabouts on price. Now, in promising to match rival baskets and pay the difference plus a penny it can give the consumers it's been losing recently the confidence not to be distracted by deals.

Where I have an issue with Asda is over perception of a different kind: quality. This is an area where John Lewis definitely outscores Asda (and subsidiary Waitrose in particular is regularly "undersold", as we know). But as we reveal (p4), Asda's got plans to address this too. And they're every bit as innovative, they say, as the Price Guarantee.