J/Z (New York City Subway service)

The J Nassau Street Local and Z Nassau Street Express are two rapid transit services in the B Division of the New York City Subway. Their route emblems, or "bullets", are colored brown since they use the BMT Nassau Street Line in Lower Manhattan.

The J operates at all times while the Z, operating as its rush-hour variant, runs with six trips in each peak direction on weekdays. Both services run through the entirety of the BMT Archer Avenue and Jamaica lines, via the Williamsburg Bridge, and the Nassau Street Line between Jamaica Center–Parsons/Archer in Jamaica, Queens, and Broad Street in Lower Manhattan. When the Z operates, the two services form a skip-stop pair between Sutphin Boulevard–JFK and Myrtle Avenue-Broadway. In addition during rush hours and middays in the peak direction, they run express in Brooklyn between Myrtle Avenue-Broadway and Marcy Avenue, bypassing three stations. At all other times, only the J operates, serving every station on its entire route.

The J/Z's current skip-stop pattern was implemented in 1988. The J/Z is derived from four routes:

• The JJ/15 between Broad or Chambers Streets in Lower Manhattan and 168th Street in Queens
• The KK between 57th Street/Sixth Avenue in Midtown Manhattan and 168th Street in Queens
• The QJ between Brighton Beach in Brooklyn and 168th Street in Queens
• The 14 between Broad or Chambers Streets in Lower Manhattan and Canarsie–Rockaway Parkway in Brooklyn