NYK and Nippon Yuka Kogyo Co Ltd, an NYK Group company, have jointly developed a new fuel-oil additive effective in dispersing sludge* and reducing fuel consumption in VLSFO (very low sulfur fuel oil; sulfur content below 0.5%). NYK and Nippon Yuka Kogyo have been investigating the properties of VLSFO as one of the measures to comply with SOx emission requirements and in 2019 developed the sludge-dispersing fuel oil additive Yunic 800VLS. They observed that Yunic 800VLS is effective against most of deteriorated compliant fuel oil, and with taking account into present fuel problem situations, we feel our main target need to be changed to reduction of fuel for contribution of environmental protection, from sludge trouble prevention. Since they were aware of it, the both companies had been developing theYunic 800VLS “grade-up” version, which is having not only more powerful sludge dispersion characteristics to cover the rest of stubborn deterioration fuel, but fuel consumption reductions.Yunic 800Eco enhances sludge dispersion and improves combustion. In three fuel consumption ratio reduction tests conducted with compliant fuel oils in Japan and overseas, we observed fuel consumption was reduced by up to 1.2% compared to when the additive was not used, and carbon monoxide emissions were also reduced.