Investors in Japan might keep a close eye on sales of the homely horse mackerel as an early warning of any trouble ahead. The good news is that in the more confident Japan of 2013, tuna remains king. So says Mizuho Securities economist Kenta Ishizu, who believes he has found a leading indicator of Japanese consumer demand that relies on two of the most common items on a sushi menu: Japanese horse mackerel and tuna. Ishizu was looking for patterns in Japanese consumer behavior that would point to the impact of "Abenomics" -- the monetary and fiscal stimulus central to the government of Prime Minister Shinzo Abe. Horse ... (full story)