Appropriate shape of a sake bottle for microwave-heating

We investigated the appropriate shape of a sake bottle for microwave-heating. The neck of a sake bottle was hotter than any other part when it was heated, and thermal differences between the top and the bottom ranged from 15 to 35 °C Electromagnetic field analysis suggested that the electromagnetic unevenness or the bottle shape might have caused these thermal differences. The quantity of sake in the bottle affected thermal unevenness, but the position of the bottle in the microwave did not show any specific tendencies. We designed several kinds of sake bottles for microwaving, and examined which was best. The best bottle was more effective for microwaving than a usual sake bottle, showing consistently favorable results even in other kinds of microwave oven. We consider that the necessary characteristics of a sake bottle for microwave-heating are as follows:(1) the neck should be wide and short;(2) the shape should be round or cylindric;(3) the height should be over 10 cm;(4) the bottom should be indented.