  With the VLBA, we have observed water masers associated with the OH/IR star,
W43A, which trace a birth and growth of a molecular jet. The water masers
exhibit the collimated distribution (1700 AU: 20 AU) and fast motions (+/-150
km/s). The maser distribution was well fit by a precessing jet model. The jet
length has extended by 800 AU within 8 years, indicating that the extension
rate is roughly equivalent to the jet speed (150 km/s). Very likely the jet was
born around the year 1960. An elongated planetary nebula will be formed by such
a jet during an extremely short period (<<1000 yrs) of the transition to form a
ptoto-planetary nebula. Then fading of the water maser jet will be observed
during our human life.
