Ryohei Kawabe (NAOJ) gave a talk on LST at the ALMA Long Baseline Workshop, which was held at 3 - 5 October, 2017 at Kyoto. He demonstrates that having a 50-m-class large submm telescope at the ALMA site can significantly enhance the ALMA sensitivity by adding such a telescope as an element of ALMA, based on the experience of 7 element combined interferometer RAINBOW, which consists of 6 10-m dishes (Nobeyama Millimeter Array) and NRO 45-m telescope. A novel idea to measure the main reflector surface of a large submm telescope, the millimetric adoptive optics (MAO) proposed by Yoichi Tamura (Associate Professor, Nagoya University), was also introduced. Yoichi Tamura also pointed out the importance of significant sensitivity enhancement of ALMA to make the proposed longer baselines more useful for high-redshift galaxy science cases in his talk. Tony Mroczkowski (ESO) presented an overview of AtLAST, an EU-led large submm single-dish telescope project. We agreed to discuss how to harmonize these currently separated efforts, and the coming AtLAST workshop at ESO early next year will be a good opportunity to do so.