South Korean exports jumped 24% in April, the fastest rate since August 2011. The main driver was a 57% increase in semiconductor shipments, which suggests an acceleration in production by Chinese electronics firms. The trade surplus reached a new high of $11.6 billion. The surplus with the U.S., however, fell by one third. That may be useful for government negotiators should the U.S. actually reopen the KORUS trade deal. Shipbuilding exports climbed 103% to a new high. That shows the government’s refinancing of the shipbuilding industry is working, but is bad news for shipping companies...