November 05, 2009: DP #150 airs.
November 10, 2009: Iwane Masa'aki posts about working on Diamond & Pearl Episode #170.
November 12, 2009: DP #151-152 airs, Iwane works on both.
April 01, 2010: Natsume Kunihiko-supervised Pocket Monster Diamond & Pearl Episode #170 airs with action cuts by Iwane Masa'aki.
Dogasu is still working on translating that Animage interview with Iwane Masa'aki from several months back. In that interview Iwane explains that he takes a month and a half to do all of the key animation for an episode by himself. Iwane spent two months working on each of the four Mega Evolution specials starring Alan and Manon due to their higher number of action cuts. He also explains that since XY began they've had 20% more drawings available to use. If you look at the number of key animators and animation supervisors working on other episodes you'll notice that there has also been a higher number of animators and animation supervisors, too.
Iwane Masa'aki isn't just fast, he's also a good action animator and even does key animation for the other animation supervisors that work on Pokemon, mostly only those who are alumni of Studio Cockpit. Iwane Masa'aki was an animator for Studio Cockpit for the early part of his career and near as I can tell he eventually left to join OLM. Iwane also worked on many of the Studio Cockpit episodes of Dragon Ball Z. I have a mostly up-to-date listing of Iwane's contributions to the Pokemon franchise here:
! Iwane Masa’aki Animation Credits (Updated as of 05 March 2015)
List Compiled by: @JacobYBM and @CookieficationJ
! *Key Animation = provided key animation drawings for another Animation Supervisor.
**No Notation = acts as both the作画監督 (Sakuga Kantoku; Animation Supervisor) and provides Key Animation alongside other key animators.
† = Sole person credited for原画 (Genga; key animation).
! Pocket Monster (70 credits, 10 solo episodes)
! EP003 (April 15, 1997) (Key Animation)
EP005 (April 29, 1997) (Key Animation)
EP009 (May 27, 1997) (Key Animation)
EP011 (June 10, 1997) (Key Animation)
EP014 (July 1, 1997) (Key Animation)
EP015 (July 8, 1997) (Key Animation)
EP018 (July 29, 1997) (Key Animation)
EP021 (August 19, 1997) (Key Animation)
EP028 (October 7, 1997) (Key Animation)
EP033 (November 11, 1997) (Key Animation)
EP037 (December 9, 1997) (Key Animation)
EP039 (April 16, 1998) (Key Animation; original airing also credits Iwane as an Animation Supervisor alongside Sakai Hiroshi and Shimura Izumi)
EP045 (May 21, 1998) (Key Animation)
EP048 (June 11, 1998) (Key Animation)
EP051 (July 2, 1998) (Key Animation)
Mewtwo's Counterattack (July 18, 1998) (Key Animation)
EP057 (August 6, 1998) (Key Animation)
! EP59 (Sole Animation Supervisor debut) (August 20, 1998) †
! EP062 (September 10, 1998) (Key Animation)
! EP066 (October 15, 1998) †
! EP073 (December 3, 1998) (Key Animation)
EP076 (December 24, 1998) (Key Animation)
! EP077 (January 1, 1999) †
EP081 (January 28, 1999) †
! EP086 (March 4, 1999) (Key Animation)
EP089 (March 25, 1999) (Key Animation)
! EP091 (April 8, 1999) †
EP096 (May 13, 1999) †
EP104 (July 15, 1999) †
Mirage Pokemon: Lugia's Explosive Birth (July 17, 1999) (Key Animation)
! EP107 (August 5, 1999) †
EP110 (August 26, 1999) †
! EP113 (September 16, 1999) (Key Animation)
! EP117 (October 14, 1999) †
! EP122 (November 18, 1999) (Key Animation)
! EP132 (January 27, 2000)
! EP134 (February 10, 2000) (Key Animation)
! EP138 (March 9, 2000)
! EP141 (March 30, 2000) (Key Animation)
! EP146 (May 4, 2000) †
! EP151 (June 8, 2000)
EP155 (July 6, 2000)
Emperor of the Crystal Tower: Entei (July 8, 2000) (Key Animation)
EP160 (August 17, 2000)
EP167 (October 5, 2000)
! EP168 (October 12, 2000) (Key Animation)
! EP171 (November 2, 2000)
EP174 (November 23, 2000)
EP179 (January 4, 2001)
EP183 (February 1, 2001)
EP192 (April 5, 2001)
EP203 (June 21, 2001)
EP205 (July 5, 2001)
Celebi: Encounter Beyond Time (July 7, 2001) (Key Animation)
EP208 (July 26, 2001)
EP212 (August 23, 2001)
EP217 (September 27, 2001)
EP222 (November 1, 2001)
EP226 (November 29, 2001)
EP231 (January 10, 2002)
EP236 (February 14, 2002)
EP243 (April 11, 2002)
EP248 (May 16, 2002)
EP253 (June 20, 2002)
Guardian Gods of the City of Water: Latias and Latios (July 13, 2002) (Key Animation)
EP259 (August 1, 2002)
EP263 (August 29, 2002)
EP268 (October 3, 2002)
EP273 (November 7, 2002)
! Pocket Monster: Advanced Generation (59 credits, 3 solo episodes)
! AG04 (December 12, 2002)
AG08 (January 16, 2003)
AG12 (February 13, 2003)
AG17 (March 20, 2003)
AG22 (April 24, 2003)
AG32 (April 24, 2003)
AG37 (August 7, 2003)
! AG40 (August 28, 2003) (Key Animation)
AG43 (September 18, 2003) (Key Animation)
! AG44 (September 25, 2003)
AG47 (October 16, 2003)
AG51 (November 13, 2003)
AG55 (December 11, 2003)
! AG58 (January 8, 2004) (Key Animation)
AG60 (January 22, 2004)
! AG64 (February 19, 2004)
AG68 (March 18, 2004)
! AG71 (April 8, 2004) (Key Animation)
! AG73 (April 22, 2004)
AG79 (June 3, 2004)
AG82 (June 24, 2004)
! The Sky-Splitting Visitor: Deoxys (July 17, 2004) (Key Animation)
! AG89 (August 12, 2004) †
! AG91 (August 26, 2004) (Key Animation)
! AG95 (September 23, 2004) †
! AG97 (October 7, 2004) (Key Animation)
AG99 (October 21, 2004) (Key Animation)
! AG100 (October 28, 2004) †
! AG103 (November 18, 2004) (Key Animation)
AG104 (November 25, 2004) (Key Animation)
! AG105 (December 2, 2004)
AG109 (January 6, 2005)
! AG112 (January 27, 2005) (Key Animation)
AG113 (February 3, 2005) (Key Animation)
! AG117 (March 3, 2005)
AG122 (April 7, 2005)
AG126 (April 28, 2005)
! AG129 (May 19, 2005) (Key Animation)
AG130 (May 26, 2005) (Key Animation)
AG132 (June 23, 2005)
! Mew and the Wave-Guiding Hero: Lucario (July 16, 2005) (Key Animation)
AG135 (July 21, 2005) (Key Animation)
! AG137 (August 4, 2005)
AG141 (September 1, 2005)
AG145 (September 29, 2005)
! AG147 (October 13, 2005) (Key Animation)
! AG150 (November 3, 2005)
AG153 (November 24, 2005) (Collaboration with Tamagawa Akihiro)
AG156 (December 15, 2005) (Collaboration with Tamagawa Akihiro)
! AG157 (December 22, 2005) (Key Animation)
! AG160 (January 19, 2006)
AG165 (February 23, 2006)
AG172 (April 13, 2006) (Collaboration with Shimura Izumi)
AG173 (April 20, 2006)
AG177 (May 18, 2006)
AG182 (June 29, 2006)
! Pokemon Ranger and the Prince of the Sea: Manaphy (July 15, 2006) (Key Animation)
! AG187 (August 10, 2006)
AG192 (September 14, 2006) (Finale)
! Pocket Monster: Diamond and Pearl (61 credits, 8 solo episodes)
! DP06 (October 26, 2006)
DP11 (December 7, 2006)
! DP13 (December 21, 2006) (Key Animation)
! DP16 (January 18, 2007)
! DP19 (February 8, 2007) (Key Animation)
! DP21 (March 1, 2007) †
! DP25 (March 29, 2007) (Key Animation)
! DP26 (April 5, 2007)
DP31 (April 26, 2007)
DP33 (May 10, 2007)
DP39 (July 5, 2007) (Collaboration with Tamagawa Akihiro)
! Dialga VS Palkia VS Darkrai (July 14, 2007) (Key Animation)
! DP42 (August 9, 2007)
DP46 (September 13, 2007)
DP52 (October 25, 2007)
DP57 (November 29, 2007)
! DP60 (December 20, 2007) (Key Animation)
! DP61 (December 20, 2007)
DP66 (February 7, 2008)
DP72 (March 20, 2008)
DP76 (April 24, 2008)
DP81 (May 29, 2008)
DP86 (July 10, 2008)
! Giratina and the Sky's Bouquet: Shaymin (July 19, 2008) (Key Animation)
! DP91 (August 28, 2008)
DP96 (October 2, 2008)
! DP97 (October 2, 2008) (Key Animation)
! DP102 (November 13, 2008)
! DP103 (November 20, 2008) (Key Animation)
DP104 (December 4, 2008) (Key Animation)
! DP108 (December 25, 2008)
! DP109 (January 8, 2009) (Key Animation)
DP111 (January 22, 2009) (Key Animation)
! DP112 (January 29, 2009) †
! DP114 (February 12, 2009) (Key Animation)
DP115 (February 19, 2009) (Key Animation)
! DP118 (March 12, 2009)
DP124 (April 23, 2009)
DP129 (May 28, 2009)
DP132 (June 18, 2009)
! Arceus: To a Conquering Spacetime (July 18, 2009) (Key Animation)
! DP137 (August 6, 2009)
! DP138 (August 13, 2009) (Key Animation)
! DP142 (September 10, 2009)
! DP146 (October 1, 2009) †
! DP151 (November 12, 2009) (Key Animation)
! DP152 (November 12, 2009)
DP157 (December 24, 2009)
! DP158 (January 7, 2010) (Key Animation)
! DP162 (February 4, 2010)
! DP164 (February 18, 2010) (Key Animation)
! DP167 (March 11, 2010)
! DP170 (April 1, 2010) (Key Animation)
! DP172 (April 15, 2010) †
! DP176 (May 13, 2010) (Key Animation)
! DP177 (May 20, 2010) †
! DP183 (July 1, 2010) (Collaboration with Natsume Kunihiko)
! DP187 (August 12, 2010) †
DP188 (August 19, 2010) †
! DP189 (August 26, 2010) (Key Animation)
! DP191 (September 9, 2010) (Finale) †
! Pocket Monster: Best Wishes (58 credits, 20 solo episodes)
! BW01 (September 23, 2010) (Key Animation)
BW03 (September 30, 2010) (Key Animation)
! BW05 (October 14, 2010) (Collaboration with Natsume Kunihiko)
! BW10 (November 18, 2010) (Key Animation)
BW11 (December 2, 2010) (Key Animation)
! BW13 (December 16, 2010) †
! BW17 (January 20, 2011) (Key Animation)
! BW18 (January 27, 2011) †
! BW20 (February 24, 2011) (Key Animation)
! BW24 (March 24, 2011) (Unaired)
! BW26 (April 7, 2011) (Collaboration with Natsume Kunihiko)
BW27 (April 14, 2011)
BW32 (May 19, 2011)
! BW33 (May 26, 2011) (Key Animation)
! BW38 (June 30, 2011)
! BW41 (August 4, 2011) (Key Animation)
! BW43 (August 18, 2011)
! BW47 (September 15, 2011) (Key Animation)
! BW48 (September 15, 2011)
! BW55 (November 10, 2011) (Key Animation)
! BW56 (November 24, 2011) †
! BW57 (December 1, 2011) (Key Animation)
BW59 (December 15, 2011) (Key Animation)
! BW61 (January 5, 2012) †
BW63 (January 19, 2012) †
! BW64 (January 26, 2012) (Key Animation)
! BW68 (March 1, 2012) †
! BW70 (March 15, 2012) (Key Animation)
BW72 (March 29, 2012) (Key Animation)
! BW73 (April 5, 2012) †
! BW76 (April 26, 2012) (Key Animation)
! BW78 (May 10, 2012) †
! BW80 (May 24, 2012) (Key Animation)
! BW83 (June 14, 2012) †
! BW84 (June 14, 2012) (Key Animation)
BW87 (July 5, 2012) (Key Animation)
! BW88 (July 19, 2012) †
! BW91 (August 23, 2012) (Key Animation)
! BW93 (September 6, 2012) †
! BW95 (September 20, 2012) (Key Animation)
! BW97 (October 4, 2012) †
! BW99 (October 18, 2012) (Key Animation)
! BW102 (November 15, 2012) †
! BW105 (December 6, 2012) (Key Animation)
! BW108 (January 10, 2013) †
! BW109 (January 17, 2013) (Key Animation)
BW112 (February 7, 2013) (Key Animation)
! BW116 (March 7, 2013) †
! BW120 (April 4, 2013) (Key Animation)
! BW122 (April 18, 2013) †
! BW127 (May 23, 2013) (Key Animation)
! BW128 (May 30, 2013) †
BW133 (July 4, 2013) †
! BW135 (July 25, 2013) (Key Animation)
! BW138 (August 22, 2013) †
! BW139 (September 5, 2013) (Key Animation)
BW142 (September 26, 2013) (Key Animation)
! Pocket Monster: The Origin Save #4 (October 2, 2013) (Key Animation)
SS027 (October 3, 2013) (BW143) †
! Pocket Monster: XY (xx credits, 15 solo episodes)
! XY001 (October 17, 2013) (Key Animation)
XY002 (October 17, 2013) (Key Animation)
! XY006 (November 14, 2013) †
! XY009 (December 5, 2013) (Assistant Animation Supervisor)
! XY012 (January 9, 2014) †
XY017 (February 20, 2014) †
! XY021 (March 27, 2014) (Key Animation)
! XY024 Mega Evolution Act I (April 3, 2014) †
XY023 (April 17, 2014) †
XY029 (May 29, 2014) †
! XY OP2 (May 29, 2014) (Key Animation)
XY ED2 (May 29, 2014) † (Animation Supervised by Matsunaga Kanae)
! XY034 (July 3, 2014) †
! XY036 (July 24, 2014) (Key Animation)
! XY040 (August 21, 2014) (2nd Key Animation)
! XY043 (September 18, 2014) (Key Animation)
! XY047 (October 16, 2014) † (two animation supervisor assistants, one chief animation supervisor assistant)
XY050 Mega Evolution Act II (November 6, 2014) † (five second key animators assist, two chief animation supervisor assistants)
! XY051 (November 13, 2014) (Key Animation) (No Credit)
XY052 (November 20, 2014) (Key Animation) (No Credit)
XY054 (December 11, 2014) (Key Animation)
! XY055 (December 18, 2014) †
! OP3 (January 8, 2015) (Key Animation)
! XY060 (January 29, 2015) † (two animation supervisor assistants: Shimura Izumi, Sakai Hiromi)
! XY063 (February 19, 2015) (Key Animation)
! XY065 (March 5, 2015) † (two animation supervisor assistants: Shimura Izumi, Sakai Hiromi)
XY067 Mega Evolution Act III (March 19, 2015) † (two animation supervisor assistants)
! XY OP4 (April 16, 2015) (Key Animation)
! XY082 (June 25, 2015) †
! XY084 (July 9, 2015) (Key Animation)
XY091 (September 17, 2015) (Key Animation)
! XY096 (October 22, 2015) †
XY097 (October 29, 2015) †
! Pocket Monster: XY & Z (xx credits, xx solo episodes)
! OP1 (October 29, 2015) (Key Animation)
ED1 (October 29, 2015) (All Key Animation, AS: Koyama Tomohiro)
! XYZ004 (November 19, 2015) (Key Animation)
! XYZ009 (December 24, 2015) †
XYZ012 (January 28, 2016) (Key Animation)
XYZ014 (February 11, 2016) †
XYZ021 (April 07, 2016) (Key Animation)
XYZ023 (April 21, 2016) †
Iwane isn't the only good animator to work on XY & Z as of late, though. Oohashi Aito, Nishiya Yasushi and Fujii Shingo have all done some very exciting work lately!