(i)     From Narita airport take Keisei line and go until Nippori station or Ueno station by:
        SkyLiner train (52 min), cost 1,900 yen
        or
        Limited Express (1 hour 12 min.), cost 1,000 yen

(ii)     At Nippori station (or Ueno station) change to JR (Japan Railway) Yamanote line and go until Ikebukuro station
        (12 - 15 min, cost 160 yen).

(iii)    At Ikebukuro station change to Tobu-Tojo line and go by express (15 min) or semi-express (15 min)
        or local train (30 min) at the cost of 240 yen (for all three kinds of train) until

        Narimasu station or Wakoshi station (for RIKEN)
        or
        Asaka station (for Hotel Cygnus)

(iv)   From Narimasu station take the bus No. 32 or 33 and go until the bus stop called "Saitama Byoing" (Saitama hospital)
        (10min., 170 yens). RIKEN is at the distance of 3 - 5 min. walk from this bus stop.

        From Wakoshi station take taxi (5 min, 660 yen) or walk (~15 - 20 min.) to RIKEN.

        From  Asaka station take the North Exit to Hotel Cygnus, which is just in front of the North Exit.
 

For more detail on how to go from Narita airpot to RIKEN please visit http://www.riken.go.jp/cmp_e/wako_access_e.html